FD works best for winging on a board at, or slightly over your body weight. I'm 80kgs and use it on a 74ltr board, getting going can be a balance act as the battery box must be out of the water to get contact with the controller. On a 90ltr board, zero issues. Mounting the battery box forward would work better but my cable isn't long enough, you need 2mtrs, mine is 1200mm.
As for gybing, it's not the weight that is the issue, but the lack of wind coming out of the gybe, you really need to keep your momentum up when gybing the wing, otherwise you slow, and there just isn't enough wind to pump and keep going so you need to drop off the foil to get the motor back in the water. Then if my battery box goes under it's all over and I restart, hence a slightly larger board for those really light days.
It is possible to mount the battery box higher, on a foam block. Something to experiment with in the future.
But is extremely fun going back and forth in 8 knots or less of wind, pisses the others on the beach off as they just can't get going. Best is a dedicated foil for FD, easy to swap foils if the wind picks up. The biggest wing I use is a 5mtr. I have both the standard and plus models but for winging the standard is all that is needed.