If you can customize and build your own rack, then I suggest using larger than normal tubs. That way it can still be a display, yet have the pros of a plastic tub.
Not my photo, but something like this:
Or maybe even look into Arboreal racks.
But tubs are more difficult to maintain ambient temp, so if you're having temp issues, maybe look into XPVC enclosures. XPVC is great for heat, humidity, and display.