He doesn't look to bad with the het, but I know what you mean.
I think Andy woods has the right idea, alot of his tanks are solo males, no stress no aggression. When I set my other tank up next year I think I will do the same, solo male amphilophus spp of some kind.
Sometimes more cichlids will stop some of the aggression but it's always a role of the dice.
I've only had success crowding or doing solo. Occasionally you'll get a laid back male, but all mine have been majority douchebags. He didn't seem that bad though.
Sweet setup by the way. I like the polys down low and the big pearsei swimming middle/top
She's looking good, shame about the fins, are you just going to wait it out and see how it goes.
Well that looks like its escalating. Still not terrible, but hopefully she won't get to much more damage.