Okay, I've tried that two tube thingy four times now. Works really great! Good swirling action in the drum, as well as the violent mix as it goes through the pump. I put 44 gallons of oil in the drum and start the heating with the spear. Two cubies of MeOH with about 440 grams of NaOH in each (that's what my oil titrates to with 4.5 as the base) ready to be sucked into the pump when the oil reaches 140F (60C). I don't worry about insulating the drum 'cuz that much mass (oil and MeOH) holds heat for a long time and the plastic drum doesn't lose heat as fast as a metal one, also, I can add heat at any time with the heater spear. I have a thermocouple with a digital readout for my temp probe. 44 gallons of oil, plus 8.8 gallons of MeOH, plus 2.2 gallons of water for the glyc pre wash makes 55 gallons. Fits nicely in a drum. 45 gallon batches are a lot better than 20 gallon ones! Now, onward and upwards! I'm looking to do 110 gallon batches. I have a 20 gallon poly drum that would work well for the methoxide.