3" behind center bob and the rails are a variable but, super sharp hull rail, high in the front and super low in the tail.
heres a couple of photos of the fin set-up. i do move them back and forth occasionally to change it up and not necessarially for wave conditions, just different rides.
the board ended up a little thinner than i thought so thats the reason the rear of the fin doesnt sit all the way down. could sand it down, lazy.