I want to be wrong but you won't get anyone else.
I am not sure you will be able to even reach the mustang guy.
I combined them when smaller. They fight a lot. It can be mitigated but never eliminated.
Everyone thought they would fight even worse when larger but mustang's were 2' each in a not-so-big tank, IIRC 300 or 450 gal-ish, and he says they have been fine, even resting side by side. There was a thread on this I wanna say 2-3 years ago. With cool photos from mustang.
He broke down the tank since but IDK where the fish went or if they are still together.