Advice on powerheads and placement

[Frozenocean]

Looking for some advice on powerheads and placement.

I have a 90 gallon (rectangular) with a mag 18 return. Central drain so the return points out from the back towards the back right hand side.

I have a mix of everything...trying to keep my SPS on the left side and teh right is dominated by a large grove of pulsing xenia. Zoes and some leathers are interspersed throughout the tank. In the middle, there is a torch, a really nice wall hammer and another smaller hammer. Leathers never seem to polp out and the

I have one Korelia 4 on the back wall, pointed to the centre.....I have a SEIO 820 that I could incorporate

My question is...with this hodge podge of coral, what do you think my best bet is for powerheads and placement? I'm willing to reinvest if it means