I don't give them moist hides. I did when they were smaller, but they seem pretty happy the way they are. I keep them in Sterilite bins that are I think 44"x18" with sphagnum moss lining the bottoms. Heating is by two-foot strips of 11" Flexwatt powered by a Helix proportional thermostat set to 85.
I dampen the sphagnum moss once in a while, but usually it's relatively dry. I've never had any problems with my snakes as long as I soak them once in a while. But yeah Kara knows what the hell she's doing so if you're ever in doubt, listen to either her or Robyn from Pro Exotics.
And yeah I know the corn is fat...his weight just went up really quickly when I started getting overrun with rats. He's going on a diet though and I've been working on giving the rats to a ball python I rescued that has always been on the frail side.