This kind of depends on ambient temperature, but you can go a couple ways. (1) you can dangle the probe on the hot side and tailor the temperatures from there or (2) you can put the probe on the cool side and set the ambient to something in the range of say 77-80 F and see how the hot side behaves. I think Bob at Pro Products told me he uses method (2). Sometimes the hot side a little hotter than "ideal", say 94-95 F, but as long as the snake can retreat to a cooler ambient, it shouldn't be any issue.