Neat website, Joe.

He may (to be generous) also have just gotten a lot of bad advice. My mom's favorite artist from the early forties is the almost unknown Dorothy Maynor, who did some opera and gospel. (Mom heard her in concert and she did spirituals for encores that Mom said were the best she ever heard them sung.) What little I've been able to find out about her seems to indicate that she got pushed into doing a lot of concerts early on, and didn't get the voice training that would have preserved her talent because the people getting her the performance venues wanted to make their money quickly.

AMG has her as "rock" for genre, but I don't think they've actually heard the music. Think along the lines of Marian Anderson and you're closer.