I have a 54g bowfront. I don't know how many pounds of LR I have but it is a significant pile (to the point where I have considered removing some of it). I did an "emergency" rush transfer when I got the tank so I never had a chance to weigh it out.
I have one clown, one bangai cardinal, one pajama cardinal, one anthias, one red firefish, and one azure damsel.
If the tank is too small I'll forgo the mandarin. I just think they are beautiful.