Currently the temp probes are just below the surface of the substrate under the hides. I will tape them to the bottom glass when I get home. Currently depending on room temperature they read: Hot side - between 88-95, Cool side - between 72-85. I spray the inside with warm/hot water for humidity as often as I can because it can go from 60-70% down to 15% in just an hour or two.

What is a good thickness of substrate? (the thicker/deeper, the further from the heat the snake will be)

Is covering the screen top safe to achieve more humidity and to hold some ambient heat?

For ambient air temp in the enclosure - If needed I could put a probe for the thermostat central in the tank, above the substrate and have it control a CHE?