I mentioned this to a Cat Tech at a jobsite today, and more or less he said what you brought out....'how big a propane tank do you have'?? He also got a chuckle out of it.
That site has 8-2MW/13.2KV, Cat diesel, 3800 gal belly tank at each unit.
It would be interesting to find out the GPHr (Propane) to run a 300/375KW.