Planted Tank Enthusiast
Join Date: Sep 2014
Location: Minneapolis, MN
Generally, I'd say stay away from two equally sized schools of fish. They'll just compete with one another visually and wash each other out.
Go with one large school of one species for the middle tier, and then build smaller groups of accent fish around that. Sounds like your top two schooling fish are lab chop/harlequin rasboras and neon tetras.
Personally I'd vote for rasboras over neons since neons are so common, and then build an Asian tank around that:
-40/50 harlequin rasboras for the middle
-10 pearl gouramis for the surface
-2 groups of 12/15 larger accent barbs for the middle (black ruby, Odessa, rosy, Denison)
-loaches for the bottom (botia, chain, etc.)
I've never kept a big tank so it's difficult for me to come up with exact numbers. Good luck.