Design Help

[Gizmoh]

I am planning for ordering the first week of Septemeber so no real rush! But it is going to be a 48x30x20 tank euro braced with an external coast to coast overflow that is 10" deep and as thin as possible to allow for a bean animal overflow. The only thing I am unsure of is where the holes will be placed there will be the three in the bottom of the overflow box (for the bean-animal) and I am thinking of a closed loop as well as some input on how the return would come into the tank without going over the back

Thanks again for all the help

Justin