And I am already sorry . . . those deform too. Luckily I won't have to move mine, as I am in Texas. I will tell you a square container is better than a round if you want to move it with a plant in it (as opposed to rolling it around on the rim, which loosens the plant and roots inside. Not good.
You know, I think someone should make a GOOD fabric pot for big plants. A sort of bag one could tie onto a dolly, or one on a platform with wheels, or something. Perhaps one could line the container with a good strong synthetic bag, then the warping container would not be such a disaster. Another good thing would be a box with removable sides, so you could take out a side and slide your fig out onto a dolly for keeping inside. If it was in a sack, no worries about losing soil or roots. Of course, I mean a good rotproof bag, like a nylon sail bag, with a drawstring top so you could top dress.
Anyhow, a bag might make you worry less about pot disasters. Please disregard this advice at will - I do not after all have to protect my precious Celeste from anything but the depredations of chickens.

I have been experimenting with those plastic milk crates. They can be purchased online for under ten bucks, and come in two sizes - 16qt which is 13x13x11, and I believe 24qt. Also, WalMart has a stackable plastic container which is a little bit larger. Both items are very sturdy. I line them with burlap or sphagnum moss, and if you stay away from stone or ceramic products in the potting mix, they are very light, with built-in handles. Being square they don't tip easily, and are easy to use with a refrigerator dolly.
Being porous they won't rot out the roots, but the flip side of that is they must be watered perhaps more frequently than solid containers. I must add that they have to be supported above ground or the roots will anchor your plant in the soil beneath.