Seems like a good idea, however I really like to be able to monitor the temp of the wort that way I know that I am increasing the ambient temp at the right time. Sometimes the wort is 2-3* over ambient temp and other times they can be 10*, so this could be a factor that would come into play. But my temp probe measures the ambient temp. If you had one that measured the wort then it could work. I wonder if you could create a computer program that could do this for you...
"Once in a while you get shown the light, in the strangest of places if you look at it right"