Advice on powerhead placement

[d3rryc]

Hey, there!

I just picked up two Koralia 4s to boost the flow in my tank, and I'm looking for advice from those wiser than I on how best to utilize them. My tank is 72" x 18" x 24" (lwh), with a mag 9 on the sump return at the upper right side of the tank. I also have a snapper driving a closed loop that runs through two SCWDs controlling four outlets scattered across the tank's bottom. My rock is laid out in sort of a "V" pattern - high on the sides and low in the middle. What's your advice on the best placement of the two Koralias and why?

Thanks!
Derry