Hi Howard,
If you leave too much oil in the sump you could over pressurise your engine and, at least, blow gaskets.
You say that you have a drainable sump plate so you can already save yourself a lot of time by draining the oil prior to starting the engine. I don't think it's worth taking a chance with the other option, it could cost you a lot more time and money in the long run....for the sake of a few minutes work.
Beezageezauk.