Here is the results of my tests in waves,
I'm very close to Peter's explanation. And like Peter, I dream about hydrofoil in waves (you will never slash a wave like a surfboard, but the feeling of riding waves with an hydrofoil is awesome)
1- I prefer to ride long mast (at least 90cm). For 2 main reasons:
Long mast allows to ride in shallow water with the wings can be deeper in the water
Long mast allows to prevent the board touching the water. When the board touches the water during turns, it stop your turn (as the board starts to be flatter on the water)
2- I love front wing with no anhedral.
Anhedral seems to be good but it is not (except constant anhedral). If you use anhedral only on tips of the wing (with flat part in the center, like the zeeko race wing for exemple, cerbon freeride wing have a constant anhedral) when you turns, the tip of the wing can ventilates more easily when it is close to the surface of the water. Flat wings prevent this
3- I love front wing with thin profil and medium AR
In fact in waves, you have a lot of acceleration and you need to control this increase of power. With a thin profil and medium AR, the power increase is smoother, then you can be concentrated to your turn.
4- I love small back vertical fin. You know there is 2 different back wings: ones with anhedral or dihedral, and the other fully flat. When I use flat wings, for waves I add a 2.5cm height back vertical fin on the back of the fuselage for waves (specially if my front wing is without anhedral). When I ride for freeride, I keep my 4.0cm vertical fin (in order to prevent yaw effect).
When you use small vertical fin + flat back wing and flat front wing, the rotation point of the foil is between the mast and the back wing, which is perfect for turns (the foil turns like a surfboard)
If you use: Front wing with anhedral, back wing flat with no vertical fin, the rotation point is between the front wing and the mast (tacks are easier, but jibes and front turns more difficult, then surf more difficult)
5- I love mast with a smaller cord.
Smaller is the cord of the mast and shorter turn the hydrofoil. 115mm is a maximum for waves (for example, I prefer my carbon mast with a 99mm cord, than my alloy mast with 115mm of cord).
6- I love to ride strapless: when you ride in small waves, usually the water is not deep enough. Then when you turns with speed, you can touch the ground and break something if you keep straps. If you ride strapless, the stress on the hydrofoil is close to nothing because when you touch the ground you fall immediately.
7- I love to ride very small board.
In Waves, I love to ride my 108cmX46cm board (we are in production now). The fact that the board have no nose makes the turns closer. This is due to the fact that the board have no inertia (in fact the inertia center is close to the foil inertia center).
Here below is the green board I use in waves