Floreana, I stumbled on this. Listened to your mix 2. It's fantastic. I think it's an excellent example of using
the SM58. I'd add, though, that the "master" version totally loses it. It's overcompressed, and too much boost in the 3Kish range. I think you're on to something with mix 2, as well as your songwriting and recording approach.
Here's an example of using only 57's to record a song.
The All 57 Song by Kelly McGuire