I've been trying things with my chondros for a couple years now in a search to achieve a real simple and healthy solution to keeping the snakes. Pretty much I'm convinced heating the water supply by day, no other heat, is the way to go without spraying. I also have a vermiculite substrate which is damp. Achieved is a day time high and night time low temperature and a humidity cycle which goes gradually up and down between saturation and maybe 60% or so. I stopped using a perch as the snakes can move around on the water tub edge and it encourages them to poop in the water which is an easy clean up to pull the water tub.
I discovered a viable limit for humidity. I poke my chondros now and again to listen to their lungs. One of my chondros after about two years of normal puffs gave me a puff of air that wasn't clean sounding and he was gaping his mouth open. This resulted after seeing what would happen if I removed my damp vermiculite substrate and having my water tub dry out for a while. I never spray, so humidity would have dipped continuously between about 20% to 50%. I've not had a retained shed yet, but the shed cycle missed this dry time. I heat the water tub during the day for humidity, so being dry the humidity wasn't there and without the damp vermiculite it was even dryer. The snakes have been in the 60Fs at night and the low to mid 80Fs by day, same as last winter when I had the damp vermiculite and water(heated by day) in the tub without issues.
Treatment I gave to the short term mild RI chondro was replacement of damp vermiculite and water in the tub which is heated by day. I maintained the power off nights in the 60Fs and days in the 80Fs. The enclosure drips wet by day with the heated water. In the morning it looks dryer, but humidity is around 60% to 70%. I also gave the snake a few drops of colloidal silver in the mouth once or twice per day for a week or so. Clean puffs of air again. I think he's fine. He's in a shed cycle now.