Daihatsu Skywing - Getting air out of the cooling system

OK, so it’ll be partly dry when you start it, and the exhaust valves, the hottest part of the engine, are in the cylinder head at the top of the engine, the last bit to get wet.

You might get away with it, but it doesn’t seem worth the risk, since any (doubtful, I’d say) benefit of having the engine turn over while filling could probably be achieved using the starter.