I am not an expert. I do own the book written by Kevin McCurley of NERD "The Complete Ball Python". On page 102 he says - "An ideal incubator will have the following features: 1 : A quality thermostat to control the temperature - probe types are the best. A simple on/off type works well; proportional ones are great but no better in this situation. I do not like chicken wafer style thermostats, they are crude and difficult to use." Now I have often heard the mantra of the proportional thermostat in regard to incubation but it would be hard to dispute the knowledge of NERD concerning ball python breeding.