Sorry for the double post..

Help with Heating

Well, I have a long 20 gallon tank and I’ve used a heat lamp for my Grey Banded King’s (Kingston) main heat source up to a week ago. I want to give him the perfect environment
Recently I purchased an under tank heater so he can warm up at night. I put Repti Cage Carpet on the bottom of the tank to prevent burns and as his substrate I use 1-1/2 to 2inches of Aspen Bedding. This under tank heater is for a 10-20 Gallon size.
My Concern is that last night he loves to burrow and last night he burrowed on the warm side of the cage which is top of the heater.

Will my snake move if it is too hot for him ?

I took a temperature reading with a infrared temp gun the surface of the Cage Carpet with the heater "On" and it ranges from 100-109 degrees F. I know thats a little warm. But if you were in outside in sunlight lets say around 85 degrees, the ground will be hotter than 85 degrees. So I’m not sure if this is bad or not.

Can anyone help me with expert advice on this situation or suggest a better one? I will really appreciate the help. Thanks -Rick