The shown body drag technique is not good, foil board rolls over when you have stronger wind if you have bigger and more floatable board. I struggled a lot using that technique (Dudotone pace 4.10) and there is also a danger of ejecting the kite unintentionally since quick release touches the board. I found that using classic twintip body drag works best but with small changes. Put your hip on the carving edge of the board, extend your arm and grab upper strap, mast is pointed to the wind.. You go easily upwind that way.