setting up my Helix

i'm in the middle of setting up my helix and UTH, and just had a quick question about temps. What is the max safe temp the bottom glass can reach without causing harm to my snake? i ask because to heat through my substrate (eco earth, about 1.5 cm thick) the glass is at about 105. while my snake doesn't seem to dig into the substrate much, i don't want to ignore the possibility that he will.

I would start out at 95 degrees and give it a few days to bring the substrate temps up then go from there. If the snake gets down to the glass 105 would not be good for it,

right, that's what i started off doing. i'm not planning on raising the temp on the helix any more, rather i'm going to start removing substrate and lowering temp to achieve the best surface temp. just wanted to know the danger points.