Not sure how a square top would work on a 17-might be a good thing as I found it underpowered (I am 200+). On the Nacra 6.0 NA I have run stock sails as well as a Sabre kevlar sqaretop with not much improvement. Most of the 6.0 guys that went to squaretops have gone back to pinheads beacause the PN hit was not made up for in speed. Again, these are very different boats, but having a new class legal sail can be a good thing.