For such a quick unplanned adoption, I think (& as others said also) that you've done VERY well & better than most who actually planned to get a BP & have posted here.
She's eating for you, so I'd hold off on changing things around again right now. She obviously likes her new place- why not, it's far better than what she knew before, and habitat changes are somewhat stressful for snakes, especially since she's new with you. So I'd wait on changing or adding hides yet- & I can't really comment on this hide since I'm not seeing the whole thing (as far as how many openings there are- is it just the 2?) From what I can see, I like it & it appears she does too, in spite of having 2 openings. I also can't tell where it is in relation to the heat- it's always best to have at least 2 hides, one in the cooler part of cage & the other with heat, & you're correct that BPs like them to feel cozy in relation to their size. I think you mentioned there ARE 2 hides? So relax...you're doing great & she looks happy, & she already ATE for you.This calls for a "happy dance".