Thinking of trying these on the back foot, anyone who has experience with them please advise

I tried them for a bit and they are much more comfortable than the dakine version.
For locating feet and ease of use, good.
Plastic stiffener can break.
You can jump, but remember to pressurize the strap.
Just a word of warning. I had them at the tail and on the first outing poked the hole in the sail positioning it for water-start. Never used them again for this reason and also found them too uncomfortable barefooted.
I use them on the foil board. Was expecting more than a few breach and uncontrolled touch downs when learning to foil. They are still on the board. More or less for foot position feedback. Some leverage. Curious how the Horue Tiny rode as a light condition windsurfing board. The half-straps really stunk for that application. Wearing booties all the time due to our cold water temps. Even with booties for windsurfing the straps felt uncomfortable in addition to not really functional. For foiling I'm more upright over the board. But still thinking without booties the half-straps would not be DaKine comfortable.
Hindsight. No footstraps or would just use conventional footstraps set up as for wave riding. Tall and narrow. How the front ones are set up. No issues with foot coming free when things go sideways.
No real issues for foiling outside of occasionally snagging the uphaul when positioning the rig to water start or uphaul. Think hook. But that might be due to my stretched out, minimal bungee Chinook uphaul. $1 less than the decade old, still functional DaKine on the larger windsurfing only boom. P.Sh.. stretched out in less than one season.
I've had a pair for one season. Really like them. So easy to locate and get into without looking down.
I haven't noticed a problem obstructing the sail when uphauling. I won't waterstart with the foil; too risky for cutting feet and legs; seen some serous trauma a few times.
Check the video here:
www.seabreeze.com.au/forums/Windsurfing/Foiling/Downwinding-in-a-25-knot-breeze--video-
I do not see him pulling up or really applying any force to them with his feet. The rear one seems to be scratching his ankle all the time.
Nothing beats regular footstraps.
Although foiling might have more risk of foot/ankle/knee injury because of potential instability in the roll axis and the anchor effect of the foil. Interested what others think?
Slingshot half-straps work well for me as I haven't fully recovered post knee op.
I'd prefer to use regular footstraps but there's always a risk of my foot not coming out or being knocked further into the strap and not having full muscle strength to compensate.
I reckon half-straps give me about 50% foot engagement of a full strap and wearing sticky sole shoes largely makes up the deficit.
Pros - I can wear any kind of shoe or bootie.
Don't have to worry about getting my foot stuck post gybe.
Con - Occasionally get the mast or uphaul jammed in the half-strap when waterstarting.
I've also been using free-ride-addicted fixings which release when pitched forward - awesome quality product.
Had 5 or so sessions on these and they worked brilliantly for their design spec once I spent the time getting confident with the setup.
I'll install them on my Freestyle 87L soon to use in our stronger sea-breezes.
www.free-ride-addicted.fr/e-boutique/paire-de-fixations-de-securite-d-g-pour-footstrap/

With normal rear foot straps I found the transition from rear foot strap to centre of the board and back a royal pain. So I bought two Slingshot half foot straps and installed them on the rear of my Alien 125. The problem is now solved. Its really easy to slide the back foot into the strap. They provide good security for my rear foot when working to windward and across the wind. They allow me to slide my foot a little forward and to the centre when carving down wind or waves. I've even survived a touchdown after a now less frequent breaching. I have much more confidence carving because I know I can quickly adjust my rear foot position if needed.
I also like to use half straps to prevent potential injury with bad fall. Here is another view from the rider with excellent view and ride. Check endless carves.
vimeo.com/jjwindfoil?utm_source=seabreeze.com.au