I agree with KGM, a thermostat is a must. Those heat mats can get as high as 140 degrees unregulated. The actual glass temp has to be measured. You can get a budget hydrofarm on Amazon for a great price out members on here could recommend a higher end thermostat if you have some money to throw around. The dinner switches work and are cheap but you have to check and adjust them any time the room temps drop.
I have a towel on folded on top of the plastic wrap which I am hoping helps insulate it. You should pick up ahygrometer also if you don't have one already. Bps are pretty humidity dependent snakes.