Four fins for Fourth board

Aloha to wherever you may be. As the title says I’m doing a quad for my fourth board (6.0 X 21 X 2-5/8) and could do with a helping hand with a couple of items.

Firstly, I understand that wider tails in general need ‘V’ out back, but how much? I started with slight V off nose, turns into 3/16 single concave, then blends to small V starting around 8 inches up. Then I cut a single channel (almost 3/8 of an inch) starting just ahead of front fins. Tail is 17". I’m now second guessing it needs more.

Secondly, Quad fin placement has probably got far to much ‘air time’ (no pun) over the years and probably why I just set mine where they look right - Front 10-3/4 up, 1-1/4 off rail. Rears 5-1/4 up, 1-3/8 off rail. This means the front of rear fin is 1-1/2 behind rear of front. I read on here that this distance will drag noticeably, so have I just answered my own question and shift it up 1/4 inch?

Steve