After doing a lot of googling and searching, I'm leaning away from trying Win 231 for now and leaning towards giving Hodgdon Clays a whirl, starting around 4.0 grains. Monday will be the next time I can get to the range; I will be sure to update.
Why?
HP38/Win 231 is excellent in the 45 ACP
FYI, CLAYS is essentially Red Dot
Powder equivalents, ADI Powders Handloaders' Guide