Plumbing, A few new Questions

[GreenSpottedPuffer]

I will start by saying, I have never plumbed a tank on my own and the one tank I had my brother help me with, I was not really paying attention Well he is not in town to help me right now, so I need help.

I just got a custom new tank from a member here. Its around 115G I guess...6'x20"deep and 18"tall. Nice and shallow. This is a FOWLR tank for my puffers. The tank is drilled in the bottom with 4-2" bulkheads. 2 Are going to be used for a closed loop and 2 for the overflow/return.

The closed loop is easy enough for me but I have no idea right now how exactly Im going to plumb the overflow/sump/return. I am going to use two rubbermaid containers for the sump and refugium, plumbed together.

So, Overflow situation...Im using the 2-2" bulkheads that are located in the back center of the tank. As I said, they are drilled in the bottom. What would you recommend? I was going to do a standard glass overflow (toothless) with a durso standpipe and then plumb the return back up through the other bulkhead to the top of the overflow and back into the tank. Only problem is, the tank is eurobraced...I would have to extend the overflow way out into the tank to be able to access inside it for maintenance because of the eurobrace overhang. Any other methods I could use to avoid this? I can't use a shorter overflow because the tank is already so shallow.

For a return pump, Im looking at buying a external reeflo pump. not sure which one yet though.

Here is a pic of the tank. Any advice would be awesome. I will have many more questions down the road but just need to get a design at least first!