I'm actually swapping out the 25's this weekend for 10's.
I have them on each side panel, back against the overflow, about 5-6" deep. Aimed to the front and up.
I can't dial them up at all without getting a sandstorm, W3 or Else mode is crazy and ugly. I keep them in C mode with 4 lights lite for each flow.
My return is a locline flare fitting, aimed dead center front glass, and down a little...........probably around 300gph.