Thanks ckuhn003. Yeah, he's gorgeous. I didn't know about dwarf BCC's until Tommy at TC Reptile told me. Then I looked in Vin's book, and sure enough, no chapter, but about 1 page on them. Page 263 in The Complete Boa Constrictor.
I have 3 good fit hides and one larger hide for Behira. She uses all of them. However, as you said, usually with her head, or more of her body, sticking out. Her bigger hide is not filled with paper towels as Shayna's (my BP) bigger hide is. She does not seem to mind. I'd hardly call that definitive scientific evidence, but it's at least one observation.