I'm 65kg and normally use a carbon Starboard Wingboard 4'9 x 26 - 70L. Went out yesterday and the wind was up and down, it was freezing and I've got a cold blah blah. Thought I'd go safe and use my 2021 5'11 x 24 - 84L Hyper Foil Sup Board, I've used it before when I was learning and thought it was absolutely fine for winging. It's Starlite construction and weighs 7.7kg. Foil was Axis 899, Ultrashort fuse and 350 stab. OMG - certainly got up easily but finding my balance and maintaining pitch control was so bloody hard, my gybes were crap, riding waves felt awkward and even my lateral stability felt awkward, lost all that super neutral easy wave riding ability I'd obviously been taking for granted. What a lesson in how much difference swing weight makes, this is despite the fact that the tracks on the 5'11 are way forward, so there really isn't as much board in front of the mast as the relative dimensions of the board would imply. It's actually quite like the Armstrong forward geometry boards in that sense. My feet were basically over the strap positions so I feel like the mast was in vaguely the right place.
Can't help wondering if the smaller high aspect foil accentuated the difference. Made me feel some empathy for the beginners on the longer heavy barges. Funny I'd been thinking that maybe I'd gone a bit short at 4'9 ..
Same here. 105kg. On 5'2x25x90l board now. Condition were marginal so took my old board 5'10x28x105l thinking it would help. Changed back to my 5'2 after 20 minutes. Could not pump, jibes were challenging, etc. Everything seemed so much more difficult.
Well I have a very different experience and not 90% of guys popular choice.
I have 2 boards and both big volume for my 75kg but 76 yo in 3 weeks so legs aren't the strongest. Having said that I am ok windwing in wind from about 10kn to 30kn with ART 899 and 799 with 350p stab and 4 and 5.5 Duotone dlabs. I have a top speed of 19.2kn and getting faster.
Now for my boards- as per photo 7ft 6in x 135l dedicated 2019 SUP foil board dead flat rocker for most of its length. I am happy on it upto about 20kn wind and jibing for me is good. Due to its flat rocker and length it quickly gains board speed so I can get up on the foil from about 10kn ish on the 899 ART. Being a big board standing up in light wind is easy for my legs.
Now the other board , 105l TE Fanatic - no issues standing up when wind is 13kn plus and my jybing is no better than on the big board.
Bottom line is smaller boards aren't for everyone and at times a bigger board can be more fun.

I'm 77kg. Using a 70l now, but it needs a repair so I went back to my old 87l. It feels huge and so much less fun.
If I try even bigger boards I find them very difficult to sail and gybe, as the bodyweight changes need to be so much bigger to turn them.
As I was coming in from my session at the local flat water spot, a beginner was getting a lesson and the guy giving the lesson couldn't even get up on their rig - a big inflatable fone with a giant 2200cm front wing. They had seen me ripping around tacking and carving 360s on my 60L and 925 foil and asked me to try their board to see if I could make it fly. I was able to get it foiling pretty easy, but man was it a dog - watch recorded a top speed of 8 mph. I completely blew my gybe too.
I guess that's and extreme example and not applicable to the OPs premise of just changing the board (same foil).
It will interesting to see if some of these new barracuda style, thin - long, boards will influence light wind wing board designs. Supposedly the forward placement of the tracks balances out the swing weight so they fly much smaller than they appear.
I'm on a thinner, longer board 5'10"*25" but with the chines the planing surface is maybe 21" and 90L for my 92kg, it's excellent. My setup has me standing almost in the middle of it with plenty of tail behind.
It does help that it's an incredibly light custom but I'm certain it's that reduced width once it's moving even a little that makes it so efficient.
I've tried shorter, wider and thicker. I won't be back on those boards unless it's nuking and I'm on a true sinker at which point I'm likely windsurfing.
I think it's not just board length but where the volume is distributed that factor in to a good longer board for winging. The starboard hypers have boxey nose and rear. This is great for Sup stability but maybe not good for winging and swing weight. My new pointy nose and tail Sunova DW 6'3x24 performs great on the wing. Sub 10knots foiling this morning on a 5m wing. No white caps and no one else out. There is No way I would have got my 5'x75L wing board flying such light conditions.
I measured my board yesterday:
Only 17" max at the chines which are very steep and quickly tapers both ends. It was this steepness at the chines that really set it apart from both the production KT, Armstrong and Appletree which were on the beach.
I'm standing basically in the middle when flying with quite a bit of tail behind me.
It's an absolute weapon in light wind.
I can't help but wonder how it would perform with a Kalama style pin tail.
Volume does not matter.
Weight, lenght and correct foil placement are what makes a board have little or a lot of inertia.
Most big brand boards are very heavy.
A custom 85l board properly built in carbon weighs 5 to 5.5 kg and costs 1000 to 1400 eur.
A light weight+10l board will surf and jump really nice, IMHO many people with far from consistent wind conditions move to sinkers and stop progressing.If restarting is a PITA you unconsciously avoid falling,avoid trying any new stuff.
Windsurfing all over again :)
Well I have a very different experience and not 90% of guys popular choice.
I have 2 boards and both big volume for my 75kg but 76 yo in 3 weeks so legs aren't the strongest. Having said that I am ok windwing in wind from about 10kn to 30kn with ART 899 and 799 with 350p stab and 4 and 5.5 Duotone dlabs. I have a top speed of 19.2kn and getting faster.
Now for my boards- as per photo 7ft 6in x 135l dedicated 2019 SUP foil board dead flat rocker for most of its length. I am happy on it upto about 20kn wind and jibing for me is good. Due to its flat rocker and length it quickly gains board speed so I can get up on the foil from about 10kn ish on the 899 ART. Being a big board standing up in light wind is easy for my legs.
Now the other board , 105l TE Fanatic - no issues standing up when wind is 13kn plus and my jybing is no better than on the big board.
Bottom line is smaller boards aren't for everyone and at times a bigger board can be more fun.

I'm one of the 10% with you warwickl.
Have been on a 118 litre Konrad for past year and loving it despite my 70kg. Didn't see the need for a smaller board, but got a 95 litre JP X Winger to see what it would be like to use a much smaller board. It's way less stable when not up but will pump up a bit easier (I suspect due to less wetted area). The JP nose dives, wobbles and is definitely less stable than the Konrad. I won't be going smaller than 95 litres as the X winger is stupidly short (5ft) and I can't see how a smaller board will assist me with my abilities. Too much of a compromise in going smaller than 95L for me at present.
In rough sea states, the Konrad will be the preferred board for me as it's way easier to use when not up and flying.
Volume does not matter.
Weight, lenght and correct foil placement are what makes a board have little or a lot of inertia.
Most big brand boards are very heavy.
A custom 85l board properly built in carbon weighs 5 to 5.5 kg and costs 1000 to 1400 eur.
A light weight+10l board will surf and jump really nice, IMHO many people with far from consistent wind conditions move to sinkers and stop progressing.If restarting is a PITA you unconsciously avoid falling,avoid trying any new stuff.
Windsurfing all over again :)
I would disagree. Volume does matter, as weight and dimensions of a board are a function of volume. Both are detrimental to ease of use and performance, while flying. If 85l is your +10 5.0-5.5kg board than a properly built -10l will be 4.5kg, thinner, narrower, and potentially shorter, all contributing to a much better feeling. And unless you foil in less than 10 knots, a -10l board will be as stable as anything bigger.
I assume that the context is intermediate riders who can pump, fly comfortably, and make at least some jibes. To get to that stage you must have slogged a lot so slogging on a -10l board with some power in the wing should not be an issue. And getting a light, small board with reasonable volume (-10-20l) to fly will be always easier with some rudimentary pumping technique.
The one thing that's clear on this thread is that opinions are all over the place. Makes it a difficult path for those of us new to the sport.
Will designs converge?
Will opinions converge?
I'm pretty different again I'm really at home on my Fanatic 5-5 x 27 x 105 litre (I'm 88kg) I've got a dud knee that hates kneeling so I uphaul , (stand up first then lift the wing) I can do this in atrocious conditions and in the wave impact zone. I can get going faster than anyone in really nasty situations plus very light wind. Every time I've dropped down in board size I pay the price dearly on slow tea bagging starts. Plus that can be the difference in getting flogged in big surf and destroying your wing or getting up quick and getting out of there. Having said all that though the few times I've ridden the Fanatics 5-0 & 5-2 they do feel great BUT the 5-5 is still very maneuverable and rides and surfs really well. I ride strapless so getting big air isn't my thing.
The biggest advantage is when you are doing a downwind and you just loose wind , I'm still able to stand and chug without burning excessive amounts of energy waiting for a gust to get going again and not having to wet launch. My go to foil is my Cabrinha HA 800 or 1000 that's it nothing bigger. My wings are 3 ,4.5 & 6 . So just because a rider a slightly larger board doesn't mean I need bigger foils or wings.
I had the opportunity to drop down at no cost as I was getting a warranty replacement for my 5-6 but after I spent a month on a demo the 5-2 x 25 x 85 I actually went backwards (winter wind) and the new Fanatics are now 5-5 same width and liters so I just stuck with that and really happy I did I love it.
The one thing that's clear on this thread is that opinions are all over the place. Makes it a difficult path for those of us new to the sport.
Will designs converge?
Will opinions converge?
No, and probably not for the foreseeable future. You can draw some generalities from the opinions (conservative rider ==> stay larger,..more aggressive rider ==> go smaller sooner). DO NOT fall subject to peer pressure. Most of us are too old for that silliness anyway. One of my over 55 buddies is happy riding protected flat water only at +30 l with no plan to change, and another buddy that can't wait to go -15l in the sketchy ocean conditions. Same can be said for downsizing your daily front foil wing size or choosing to use straps for jumping, or even the type of riding you want to do. Get opinions but march to your own tune!!
FWIW, at 64 and 78 kg and winging for almost 3 yrs, I ride a 78l/4'10" strapless board ( bad knee). I've tried and owned smaller ( down to -15l) and just don't feel comfortable with it as a one board quiver. I still own a 1900 sq cm/ 107 cm performance oriented front wing and love it for light winds. I can do all my transitions on it in 12 kts and I just don't care what the group consensus is. Who knows, in a few years I might upsize my board as the body ages. I'll feel lucky to even be riding at 76 like Warwickl