@Jack Crosby I'm gonna agree with Jim. The last time I pulled my engine (when I had the transaxle rebuilt six or more years ago) I also pulled the sump plate and screen, which I never touch, just to check it and re-seal everything and after something like 12 years the screen was clear. It looked like the external filter (NAPA Gold 1515) was really doing all of the work (the screen would only catch something the size of a pebble, anyway) and I haven't bothered with messing with the sump and screen since.
To your point about Alan's method, though - That's an old-timer mechanic's trick that works like a charm, as you've found out!
Plus, you get to schmeer RTV all over yourself while prepping the gaskets!