Hi Joerg, Happy New Year. Indeed a bit tricky, but spring will be here soon and hopefully we'll all be out on the water!
Klaas did try the Wing with a normal surfboard, which they are also doing on Maui/Cape Town - seems you need quite a bit of wind for this as obviously the Wings do not have much lift vs a kite or sail. But of course easier than a classic windsurfing board, due to the size. Of course in lighter winds, a windsurf board will be better, but generally a wing board is so much better in all conditions.
We have used the Bee in non-planing conditions, but not in the waves for waveriding, but am pretty sure it would work, similar to how the normal wingfoil boards work, once you are on the wave, you can just de-power it behind you. Guess it's something we will see more and more of as the sport and products develop further!