Okay, so as it turns out, I was not remembering correctly about the research I had done before (which was on dating Polaroid prints, not original negatives). So I'll have to look more into that tomorrow. For now, I'm starting through scanning my negatives, which is taking a while as I'm scanning them very high-res (AMAZING amount of detail when you zoom in on the results). First few are:
Stan Hack, Lou Stringer, Hank Leiber & Billy Myers - 1941 Chicago Cubs
Herman Franks, Mickey Owen, Don Padgett & Sam Narron - 1939 St. Louis Cardinals
Larry Gilbert Sr. & Larry Gilbert Jr. - 1938 New Orleans Pelicans
Arky Vaughan - 1942 or 1943 Brooklyn Dodgers
I also located a few glass plate negatives that I've never attempted to scan before, so I'll give those a shot tomorrow as well.