The ones I've grown never seemed to have large root masses, more wide than deep so I would choose a wide pot at least 12 inches deep. I would also keep a saucer under the pot or else your baby is going to creep out the drain hole and take over the yard.

I grow them for fruit and have only gotten fruit from pot grown vines after 3 years (even though they bloomed every year) and in large 3 gallon pots. You get a lot more fruit from growing them in the ground but they tend to take over the world.

I am about to transplant mine as well. Going from a 6" pot to a 3 gallon container with a trealis. They are about 2 feet in height and already giving me flowers. My plan is to contain them on the 6x2 trealis. A modified version of how kiwi or grapes would be grown. Since I love pruning, I imagine this will be very rewarding.

Being my first run with the fruit bearing breed, I can only confirm that once they are in the ground they can over run a wall and surrounding plants in no time. Constant pruning leads to constant flowering I have learned with my previous ground planted ones. I pruned every week and pulled 30 - 40 flowers each time and let them float in my pool. A sight to see. Enjoy M-G-B.

Thank you both for your helpful advice!