Woah, post back from the dead!
Yeah, I've given up worrying about this and I'm making sure to mist once or twice a day. Zoot just shed again this week, and it was perfect again, so I must be doing something right.
I'm changing out her cage this weekend, and I'm switching from the Aspen to Jungle Bark with some CocoSoft mixed in instead. The Aspen does tend to mould a bit and the smell is less than pleasant. If it help the humidity stay up as well, all the better.
Zoot will be moving into a larger enclosure next year anyhow, and I'll switch to a radiant heat panel at that time.