Actually, that method works just fine. Using a reliable digital thermostat for the hotspot, and a dimmer plugged into the same thermostat for the other heating pad, dimmed down to the appropriate temperature, maintains a very steady temp. And just in case the dimmer should fail, it's still plugged into the thermostat and will only get so hot.

Just be sure to buy a QUALITY thermostat, not some Zoomed, Alife, Big Apple Herp or ESU crap. Those are the ones that will fail on you and cause a fire or burn your snake. Getting a Johnson Controls, a Ranco, a Helix or one of the Herpstats, and your snake will be much better off.