Hi,
OK. I think, since your changing tanks anyway it might be a really good idea to have a thinner layer of insulating material on the bottom of the tank.
The problem is your heat mats are trying to heat through way too much substrate and, as a consequence, have to run hot enough they could seriously burn your snake should he burrow down at any point.
Try newspaper - no more than two layers should be fine.
Measure the temps directly on the glass first and try and get them to be regulated around 94f.
Then measure the temp inside the hot side hide - but make sure your snake can never come into contact with temps hot enough to crack glass.
dr del