Random thoughts about optimizing smaller boards - interested what others think?
I'm not particularly wedded to any of the points below - just what's working for me after some experimentation.
Brands have lost interest - freeride windfoil development is up to us

None of the other foil disciplines appreciate the advantage/froth we have riding swells downwind

Boards designed for higher winds (>15 knots) have unnecessary surface area - too wide, too much nose, also too thin.
Does anyone like long noses? Potentially you might recover the odd touch-down that could bury a short nose, but for that rare occasion you're flying around with extra swing weight and air buffeting.
Board length is ok but cut a chunk off the nose and stick it behind the foil where's there's no penalty

Width <64cms catches the chop less upwind and downwind.
I'm 80kgs and need about 110L to comfortably uphaul in swell - I might only need to do it a couple of times all winter but it's obviously handy offshore or midriver when the wind disappears. Thickness (>15cm) seems like free volume, I can't feel any disadvantage - Simon has figured it out with his Oz Custom.
For light winds thinner boards with more surface area are fine - volume to uphaul and also more planing area to get on foil easily.