The rotational pull of the crank & rods is pretty strong, so I've always adhered to the directional louver deal, which I open up a bit.
Crank scraper helps with pretty much anything you do.
Dimple-die on the round holes should help them act one-way, but a bunch of small round holes doesn't seem as effective, though they will obviously drain.
Easy enough to visualize the pan environment by rapidly stirring soup, though there's a bit more going on (pistons pumping)...