Tip for 5 gallon containers.

Buy a 1/2 Sheet of MDF board, don't get fiberboard
Have it cut into 1'x1', it should make 32
Buy a boatload of the 1" casters
Screw 4 into each board

Viola - Sliding plants.

If you need to make 32 of them, that's alot of wheels. Personally I don't move my plants, just twist them, unless they need rotated, but I'm in hydro, so I just swap out the netpots