I want to use MP40's, but...

[Arok3000]

Please refer to the following awesome MSPaint drawing for reference.

The back of my tank is 30" by 18". The overflow in the middle takes up a bunch of room, and the returns on the sides have bulky elbows which basically prevents putting an MP40 anywhere on the top half of the tank.
I orignally wanted to run two MP40's on this, but it looks like the area available consists of a small 8.5" by 9" window in the bottom corners. Is this really feasable, or am I destined for a sandstorm? I'm under the impression it would just make a mess and not provide much useful flow.

Alternatively I could go with some Tunze 6105's, or some good old Koralia's.

I forgot to mention up top, this tank is a 40" long 3 sided tank, so the powerheads are hopefully moving a good chunk of water a fair distance.