+1 for humid hides and proper hydration. A hide or two with some damp sphagnum moss and access to fresh water should be all you need to see your snake through a shed and keep them healthy. You'll probably only run into real health issues with humidity when it gets to levels that are 30% or lower -- the same levels that give us humans issues as well.
Tossing a little water into coco-based bedding like Reptichip or EcoEarth and wouldn't hurt. I do that all the time during the (very dry) winters here, and I've never had a problem. Just don't totally soak things, allow the bedding to dry out between dampenings, and you'll be fine. Mixing a bit of sphagnum moss into with the overall bedding itself helps, too.
I tend to do my water changes, mistings, and the like right before sundown. Humidity naturally spikes at night, so it's more natural for it to rise then. Pythons are also more active at dusk, dawn, and overnight, so that'll be the time they're actively looking for their water bowls and mist beads to drink.
Good luck!