Kirt,
Just wondering if you have had much of a chance to compare the performance of the 17 and 21m kites.
Given the same luff length and the different sheeting positions I would be surprised if the 21m is any better.
I have no data on which to base this statement it's just that I would of thought the lift 90deg to travel would be higher possibly resulting in more hull drag.
Just a guess. I'm very interested in your experience.
Regards,
Phill