Well I asked around and it turns out that the bubble terminator 20L is a bit overkill so a sump redesign is in order. I also looked around at the price of plumbing parts (esp union ball valves) and decided to go with the classic sump/refugium setup instead. One side benefit of this plan will be the ability to save one of my mags for backup in case of pump failure.
So If I only get one tank other than the 40 for the sump I want it to be as big as possible. That leaves me with the 30.
The tank is 16" tall and the tallest baffle is about 14" and the shortest 12"
The return section is sized to fit a Octopus recirc110 with a little room to spare
from right to left skimmer section 13" return section 8" and the fuge is 14" I plan on Placing a ball valve above a T in the return line to feed the sump.
This is just a rough draft and I would greatly appreciate any input.