I didn't see a thermostat for the UTH in your equipment list. If you don't have one you need one, you're just lucky your snake hasn't burned itself yet.
This tub is great for one snake since the lid latches very securely and it's about $20. You just need a UTH regulated by a thermostat so it creates a hot spot at 92*F on one side:
https://www.lowes.com/pd/Hefty-25-Ga...Lid/1000505547
Since it holds humidity extremely well you can use paper substrate and not the eco earth, unless you really want to.