The rule for bp's is one girth-sized prey item a week. Remember, they can open REALLY BIG and their skin stretches so dont be afraid to feed a large prey item, as long as it is not any bigger than the largest part of their girth.

As for the rubbermaid containers, someone else should pipe up about that. i use a 20g also and it works just fine for me. i have a UTH and use Eco-Earth as bedding and a large water bowl. the humidity is about 60-70% constantly. i also partly cover the top with a t-shirt.

Welcome!!!