That is one crazy board and some mad skills to get it going.
I built one last year and tried it a few times in stronger winds. The vid is from the first voyage, I got more comfortable on it but as always its a world of compromises. And IMHO if I can't up haul it easily and its too narrow to get leverage on the rail the trade off for a marginally livelier board is not worth the hassle. For me its about having fun and a little bigger board makes getting going, getting back, bouncing up off chop and recovering in between waves easier and easier = fun.