it all depends.
You can choose a bigger kite, which you can just park and pulls you. But then on upwind you can go less upwind. A smaller bow type will be hard on downwind tracks.
I used for the same course a Vegas06 16 and R7 14.
Downwind the V6 16 was the clear winner, I just parked it and it pulled my downwind with speed. The R7 14 I had to loop all the time, since it always went to the edge and didn't stand further back in the powerzone...
So you win here, you loose there. Same with the boards, since you can go fast with the twintips...but also depending on conditions.
In Fuerte the speed part (not really downwind) had flat water, and here the twintips overtook the surfboards, when it was close. But then again, upwind the surfboard win again.
It all depends, and 2 knots can again make a big difference...