Well, like I said, the cypress is fine. But since you got her from an expo, mites are a real possiblity - no offense to her breeder, but at expos, the snakes are exposes to all manner of things. It just goes with the territory. And it'll be very difficult to spot mites quickly if she's on cypress. You can solve the humidity problem by covering the screen top with wax paper, tin foil, or even a towel and misting a little every day. But the choice is up to you.

And do you mean that breeder said the fuzzy rat you bought her is the same size as the hopper mouse he was feeding?? I'm not sure I understood that part of your post. Either way: 1) Mice are healthier for baby boas than rats. Rats contain more fat and mice are easier for a boa's high metabolism and more sensitive system to handle. They switch very easily from mice to rats when they get older. All of my boas are kept on mice until they are able to eat adults. They are then switched to a comparitively sized rat (so they are usually over a year old at that time). 2) The prey size is still to large. You should not see a lump. Or there should only be a tiny lump. Boas can be prone to regurging and too large a prey item can cause that. Smaller is better. It is virtually impossible to underfeed a boa as long as they are getting something every 10 days or so.

Sounds like you got her for a good price. Normals would sell at an expo for around 40-60 depending on pattern, but since she is a pastel, that adds to her value. I don't know exactly what you paid, but under 100 is pretty good. Congrats again!