need help with fin position

Hello to all. I’m in the proccess of building my first tri fin HWS. Measurements of the board are: 5’10’’ x 2.25’’ thick, 11.75’’ nose, 19.5’’ mid, 14.25 tail. The problem is, I have no idea of fin location for this kind of board (Previously built boards are all single fins, and a fish). Can anybody give some advice? thanks in advance, hope someone can help.


rear edge of center fin to tail: 3.5"

rear edge of rail fins to tail: 10.5-11" (further up stiffer)

rail fin toe-in 0.25 inches over a 4.5 inch base, or toed 3 inches outside the nose

rail fin cant 4-6 degrees

rail fin rear distance to rail 1.25 inches