Well I found bigger cages if they are needed. I don't plan on getting a female. I want to start off with a male since they are smaller and once I've had the male for a while, MAYBE get a female. So I want to hear from a few more boa keepers before I go off and buy a cage. I won't be getting a large cage like this at first. I will probably start off with something smaller since I plan on getting a baby and keep it in a tub.
Another question. What heat pad should I use for a tub for a baby? I know to use it under a thermostat and plan on getting one when I get the other supplies. And what surfaces are safe to put the pad on?
You really don't need a 6x2x2... The one you listed would be fine for a small adult, otherwise move into the 4' range.
1.0 Normal Ball Python
1.0 Western Hognose
0.1 Brazilian Rainbow Boa
1.0 Hypo Columbian Red Tail Boa