I’m working on a MIDI guide track for part-learning, and am heeding the advice of Anders Edenroth, who suggested moving beyond a simple clave-style click track.
Even though the final track will be a cappella, there is value in giving a rhythmic foundation that helps singers feel the groove as they are learning the piece. Simple piano guides might not help in that respect, and neither will any simple quarter note click.
So I crafted a simple drum groove in Pro Tools (In Logic or GarageBand, I could have searched loop libraries for the right effect, but I’m most comfortable in Pro Tools.) Now the guide tracks, though quantized for accuracy, will still have a groove that will hopefully empower the singers who use it to really engage with a clear rhythmic feel.