More than likely 3 ft of 11" Flexwatt on the backwall. Tie that to a regular Herpstat and youre golden. Incubators that are small, such as mini fridges and ice boxes and wine coolers are pretty tough to mess up or throw out of wack temperature wise. The probe is subjected to the interior temps, the inside is weather proofed from the outside.

1 3ft sheet of Flexwatt stuck to the back, properly soldered/connected/crimped/whatever to just ONE plug. Bam. Good luck. I have a thread up somewhere about how to build one, but then again so do a lot of people. Any specific questions, my PM box is open.