I've grown 3 stem 9' tall plants in a 5 gal bucket but the plant did not reach its potential as to fruiting and required constant care.

Smaller determinates do better but still need a fair amount of tending. Dwarf plants would probably be fine.

Bigger is easier to do better.

I've grown in 18 gallon containers and had great success. The larger the container the better. If you decide to go with large clay containers try to get the glazed ones as they don't dry out as quick as the unglazed ones. Oh and make sure to a potting mix and not soil because soil can compact too much in containers.

Happy gardening

I use 16" unglazed clay pots for some of my plants and they work really well. I don't know the equivalent in gallons, but the plants seem quite happy in them, even larger indeterminates. The plants almost always grow larger than expected, and it's nice to have the extra weight of the clay for stability. Do keep a watchful eye on them in hot weather, since the soil dries out a bit more quickly than in plastic.

MA