I have been trying to tell you that THIS IS WHY YOU NEED A THERMOSTAT. Using bedding alone will not prevent thermal burns. The snake CAN and WILL move the substrate.
You seem to be asking questions and when you get an answer you don't want, you ignore it or find some other ambiguous reason or excuse as to why you can't do what we suggest.
If this is really how you want to take care of your animal, so be it. Just know that you aren't taking care of your animal in the best way that you could be.
I am sorry if this comes off harsh but you are just not being cooperative at all. If you want help, take our advice.