Depends on more than pot size. Color is important as well as style. Pics would really help.

If it's a pre-bonsai, that implies more trunk thickening and growth. I wouldn't put it in a bonsai pot in that case- all of that development will slow and be much more drawn out. If it is considered to be 'finished' to you, and you want to focus on maintaining it, with some ramification/filling out left to go, then I think a bonsai pot is in order and the sizes you are looking at seem in principle to be in the ballpark, though I think I would avoid a 4" deep pot with the thickness of trunk you have mentioned.

ez

LINK: How to choose the right bonsai pot.

If you wanna follow the traditional Japanese Guidelines there are a few simple rules and everything else is up to personal preference. The length of the pot should be equal to the height of the tree. The Thickness of the Trunk Base should be the same as the height of the pot if not possible then the depth of the tree's canopy would equal the pot's height. and non of the branches should go over the edge of the pot.

check out these different Bonsai pots. In Stock Available.

Bonsai Supplies Pots Etc.