I've been using a 9-1/2" Harbour HP fin (trailing edge set 9" up off tail) on my 9'6" Banana for years. Works great for me. Start with the trailing edge 8-1/2" up and move it forward in 1/4" increments to loosen up your turns or back in 1/4" increments to stiffen them up, according to your personal taste. At first glance, the fin may look to you as though it should spin out. But look again and you'll see that, despite its relatively slender outline, it actually has quite a bit of base. In fact, these fins hold the tail in quite well and give good drive out of turns.