Based on what you've read in this thread, where on the back wall would you place the four bulkheads? Maximum of 2 in any of the wall plumbing cutout sections (the spaces between the framing that are just plywood). There are four cutout sections on each side of the back of the tank.
Top
Mid-Upper
Mid-Lower
Bottom
and of course they are on the left or right side of the tank.
In example,
Right Bottom - Two
Left Bottom - Two
or
Right Mid-Upper 1
Right Bottom 1
Left Mid-Lower 1
Left Top 1
Let me know where you'd put them.