My return from my sump comes over the back and the outlets are right at the top back corners facing the from of the glass. This is only about 200 gph of flow.
I have 2 tunze 6025's, each facing directly across the tank. One is in the lower back corner, one is in the upper front corner. One gets the flow along the lower rock work, the other gets the flow moving along the front. Kind of a mini cyclone, and only one powerhead is visible.