Isaac-1

I am just getting started growing bananas and have a couple of small banana plants (18 inches tall or so). I live in Louisiana just north of the 9a / 8b line, and given what I have read it sounds like it would be smart to overwinter these small bananas indoors before putting them in the ground in the spring. I plan to let them overwinter in a mostly unheated sunroom, during the winter months the highs in this room often get into the high 70's, and lows never get below freezing (a heater is ran in there for the various plants when there is a severe freeze).

Now for the questions, what size container do I need for each banana plant, assuming they will be going into the ground after the last freeze, likely around april 1?

And do you think these are acceptable overwintering conditions for a small banana plant?