Plumbing...suggestions? Added a drawing...

[Parker]

but I'm considering putting my return in the middle of the back down low say 3" off the bottom

The only problem I see is, If the power goes down you’re going to siphon all the way down to the level of your return. A closed loop return down low would be fine, but not a sump return even with a check valve, they have a tendency to fail, it doesn't take much to keep them from closing all the way. This is assuming that your return is through the tank not over the top.