RE KFC fryers
The very first one was a model 40 Presto, then Colonel Sanders started using Mirro Matics, I have one from the 60s, it is a 16 qt Mirro Matic, the only difference in it and the normal Mirro Matic is the weight assembly, A good friend was the manager at KFC from 1965 up into the 70s, he told me the whole process, Peanut oil is heated to 350 to 375, the breaded chicken is added, that size cooker will hold 4 small frying chickens, then the lid is put on, when it begins to jiggle, time 12 minutes, take off heat and unscrew the pressure release in the weight, it works great,