Substrate...blah...

[SCWood]

Paper towel. They get used to it pretty fast and its economical and easy to replace. Most top breeders use it.

IDK mama wants to keep it looking natural she hates the look of paper!

Repti bark is said to be fine for ball python and I believe for your boa as well. I've never used it though, so I can't offer personal experience, the only thing I would worry about is a tooth getting stuck on a piece of bark. I'm sure someone who uses it will chime in. Personally I use about a 50/50 mix of aspen and eco earth. Bottom inch all aspen, top inch to 1.5 Of eco earth. Loki tends to mix it up as he slither through it and beds down.

Well, I made some coco in a bucket and had extra so I let it sit to dry and now it has buggies in it >.> moths and all that weird nonsense so mama is using it as potting soil. I just love the bark because it's not as dusty and smell so nice.