Think I've found a decent solution for the humidity problem. Misting was doing next to nothing and the humidity would dive back into the 30's right afterwards so I tried gently pouring a cup's worth of warm water around certain spots of the tank so it'd soak into the coconut fiber (while still leaving plenty of dry places so he doesn't risk getting scale rot, and I didn't use too much that it'd pool at the bottom or anything).

The humidity as a result has bumped back up into the 50's and has remained there even after several hours. So I think as long as I periodically water the substrate enough to maintain a "reservoir" of moisture things should be good, and all I'd have to do for shed time is be more liberal with how much water I use for the coco fiber to absorb along with misting.