In day to day airline operations they would hardly have a chance to drain down to the lower cylinders, if the engines were in reasonable shape. After a week or so standing a pull though by hand was always the accepted way. When you meet resistance pull the lower plugs on that engine and drain it out. I don't recall having to drain any of them, but maybe ours were good engines.
We also seem to have forgotten the experience of the pilots on the P-47's etc. as at the begining of this thread. Not much!! You will also see on some WW2 films that the mechanic/fitter started the engine as the pilot ran to get in. The mechanic/fitter knew a lot more about starting the things than the pilots.
Speedbird 48.