I have a 300SE and don't need to remove the air filter housing but there is probably more clearance in the 300SE engine bay.

I'll have to try loosening the oil filter slightly before removing it while the main oil pan is draining to see if the will also allow some of the oil in the filter to drain out. I suppose I could take a scribe awl and punch a hole in the bottom of the filter to let air in.

Good point about the copper washers.