Quad fin placement on 8'3" MLB ???

Hello out there: I just finished an 8’3" soft round tail MLB Concave to rolled V out the tail

I want to put a quad set up on the board 18 X 21.5 X 14.25 x 2 7/8

I have placed quads on small boards and was wondering if there is a standard template based on the length

of the board? I guess what I’m looking for is the distance off the tail to the trailing edge of the rear fins. This being the point where I should begin my calculations.

I.ve been told 6.25" is a good starting point using 2.25" from the rail

I know everyone has a different idea of fin clusters but I’d love to hear other ideas from the sway zone…

Thanks

LB