I'm glad you checked on temps.- you shouldn't need to check hourly though, are you not using a thermostat?
What you might do in the larger hide (instead of the TP roll, maybe take them out): loosely crumple* a couple paper towels & stuff them in there. He'll be able to smoosh himself in really well & I've found many baby snakes (of all kinds) seem to like how that feels. I have a feeling he tried the tubes but they aren't quite the right thing.
*Another option with paper towels: layer a couple towels & tear/shred them into strips, then toss strips into a jumble, & use inside the hides as before. Snakes love to move thru and hide in things in the wild...grasses, leaves, crevices & holes.
When you use paper towels in a hide this way, they can freely move thru it but everywhere they go they feel 'surrounded', which to them = "safe". It also shouldn't impact the temperature too much (as long as it's not packed in like insulation).