Habba huts should work well, the small ones are working great for my BTS, pretty much anything works if it is
a)non toxic
b) provides a snug fit for the bp
c) possibly retain more humidity
d) easy to either replace or clean.
Interesting you suggest habba huts, I've been told they aren't secure enough? Although, I think they would work just fine if you covered them up with substrate a bit. ,