Hi all,
So about a month ago I bought a second hand (hardly used) windsurfing set that was around the 2010-11 era.
155l board, 5.8m sail, 430 mast. Also managed to get 4.5 and 5.4m sails.
Have been out most weekends since in around 10 to 18 knots.
Been planing a few times, starting to use the harness a little, and learning beach starts.
A few questions about progressing and getting more gear.
I feel like I could go with a bigger sail. What would be a good next size up , and could it fit on my 430 mast?
I find it a lot easier to get power in the sail when I'm not in the harness. Is this something to do with how I've set up or is it just practice and getting used to it?
I can stay upwind fine and go across the wind, but going downwind is a bit harder. Is this normal as I spend most of my time going upwind or could it be a technical thing. When it's windy I feel like the sail is either going to throw me off or not get any wind (going downwind). As a result my gybes (non planing obviously) are way behind my tacks.
Cheers
A 7.2 or so would be good , I wouldn't go much smaller than that. Unfortunately it probably wont fit your mast. When buying a bigger sail make sure it matches the mast curve bend of your new mast. There are charts to get that right. Dont forget your boom , is it long enough for the bigger sail ? and its also not a great idea to use the boom on max extension. It helps to have buckets of money , but there is a lot of good cheap second hand stuff out there.
Power ? Is the boom high enough , about tit to shoulder high , and harness lines long enough , arms almost straight . Also make sure the lines are balanced left to right , should be about equal pull on both arms.
Downwind is harder, its a practice thing.
Without seeing what your doing I cant comment on your gybing.
A couple of tips mabee:
Start practice in very light wind,
Look around the corner to where you want to go and complete your turn ALL the way before flipping the sail,
When planing into a gybe , go down wind 30 degrees be aggressive and dive into the corner. It is scary at first but if you don't you kinda get stuck standing at the back of the board going directly downwind ,and its hard to finish the turn.
Windsurfing is not easy , But it is awesome , if you want easy try Kitesurfing. 
I would look at 6.5 ...most will fit your 430 .
yes it sounds like your under powered ..do you sail in Perth or safety .?
i would ask a fellow windsurfer down the beach next time ..to see where you could improve ...as he or she could see you sailing .
i was lucky I had two mates that got me into it ..and had teaching off them all the way .It took me a year before I could gybe without issues ..yeah I was a bit slow ..
keep at it ... And get into those straps .
Keep this in mind .at present ....I couldn't do one run without being in the harness or the straps the pressure is too much ...that's when you know your powered up .so when you can't hang onto the boom for long ..
that s the feeling you need ..to fully plane.and stay on it .you only unhook to gybe .or tack .
you start with bigger boards and smaller sail then progress to smaller boards and bigger sails ...that's my lesson for the week .
enjoy that's the main thing . 
Most 7m to 8m sails will rig on a 460cm mast so a 6.5 freeride or cross over sail would be about as big as you can go on a 430m mast. Beware that masts bend differently, so make sure you get a sail that is compatible with your brand of mast.
Tips
As Tardy says - light wind practice, this will progress your sail handling faster than any other time on water.
Don't be afraid to ask questions about your rigging or gear choice, most windsurfers I know are happy to waffle on about anything to do with windsurfing coz our partners never let us do it at home.
Commit... to the harness, to your turns, to everything... better to commit fully and stack than trying half heartedly, you'll learn more.
Get a big shed or garage 
Select to expand quotej235 said..
I can stay upwind fine and go across the wind, but going downwind is a bit harder. Is this normal as I spend most of my time going upwind or could it be a technical thing. When it's windy I feel like the sail is either going to throw me off or not get any wind (going downwind). As a result my gybes (non planing obviously) are way behind my tacks.
Is this on your 5.8 ?. What Brand/Model is your sail and mast ?
