I've restored a few of these pumps but never have tried dispensing. I could see where you would just watch the cylinder drop in level or just pump in the three gallons into the cyclinder and dispense with just one guy. But I'm not sure what they did. I bet they figured out a way to do it with just one person, I think it would be hard to man with two guys all the time. But I dont know. I'm sure they were good about not over dispensing, as that would cost them $.