What size shipping boxes?

Hey guys, I'm about to ship out some ball pythons and I'm not quite sure what size boxes would work out best.

I'm buying my supplies from Ship Your Reptiles, and viewing their chart... lots to choose from. So, for you guys who are experienced in shipping, what size box to you typically get for babies, juvies, and adult ball pythons?

should I go with the Medium species chart?

Medium species, yes.

For Babies and Juvies I use 12 X 9 X 6 boxes. ;)