Just a few answers to some of your questions.
I usually heat the oil to about 120 degreesF.
My processor will handle about 250 gallons per batch
I use commercially designed immersion heating elements for veg. oil use.
The processor has 2 elements in it,each one 3000 watts,,240 volt,,single phase,
The wash tanks have a 6000 watt element in them.
It usually only takes about 1 1/2 hours to heat up the oil,or oil and wash water..
Remember I use commercial elements designed spacifically for bio/diesel production.They are more expensive ,but their life expectancy far exceeds trying to use an element designed for a water heater, Water heater elements will not last very long in oil,, trust me ,I have already done that!! Duff Streeter www.michiganbiofuel.com