i use packing peanuts at the bottom of the fabric containers.
i have a mango ion a 7gal, and pretty happy with the results.
havent moved it much, but, that doesnt seem to be a problem
i figured if i really need to move it a lot, i would put it in a larger plastic container
temporarily to move it, then take it out.
since then i have taken a knife and poked holes in the sides of all my plastic containers.
i was much easier and faster than repotting 50 plants.
i just bought a 18inch tall candle tree (Parmentiera)
the roots were 8 feet long wrapped around and around inside the pot.
it took a 1/2 hour to tease them out without breaking them.
i transplanted it in a kitchen tall trash can (LOL)
i put holes all around the sides with a knife
hopefully, it will stop the roots from circling the container.
this trash can is sold with prefab holes
i used newspaper around the sides to keep the dirt in
it owrked great for several months until the paper fell apart
then, when i moved it, little bits of dirt fell out the holes.
when the plant died, i looked at the roots
nothing wrapping around at all, and lots of fine roots.