Suggestions and help with plumbing my tank please?

[jvision]

You don't need an overflow box. My 37 is drilled at the top (like the right hole), and I just have PVC draining right into the sump. Since I only have one hole, my return comes over the back of the tank (like a canister filter), but you could return thru the other hole... not sure if that's what I'd do with the 2nd hole.
I'll let other 'plumbers' chime in.