Fin ????

For that size board the center fin seems very small unless it's some type of 2+1 or tri fin setup. Long boards 9'0 and up use a 9" center fin; my 9'2 came with a 9" and my 9'6 has a 9.75" center fin. I ride strictly single fins so larger center fins may apply. Anyway check out True Ames, they make every type of long board style fin you can think of.http://aol.trueames.com/
P.S. moving the fin forward in the box will loosen the board up, moving it aft will give the board more stability

 

I use the Wingnut Long rake on my board I belive its a 10 inch fin. It turns really loose and You can still ride the nose and I still have a good amount of speed.
On my 9'6 Wynn I have it set almost all the way to the back of the fin box with about a 1 inch gap between the fin and the box. My stability is good and still have good looseness and easy turning. I only have a single fin set up so if you have a try fin it may perform differentley

 

I like my longboards loose too. The single fin ride is smoother, but putting in the 3.5" sidebites, and a pivot (vertical, small tip) fin pushed forward in the center box like this one pushes the whole fin cluster forward (as opposed to SF where the pivot point is always further back) and allows you to turn more like a shortboard - i.e feet planted. My longboard is a 9'0" x 22" x 2 7/8" lots of rocker and i use a 7" fin


Hull Flex
The Hull Flex was designed to be used on retro style boards. The high aspect outline with thin flex offers a shorter turning radius with lots of power and blinding quickness. Smaller size can be used as a 2+1 if desired.