Re: Tactful corrections of band members
The record & playback suggestion's the best way forward imo. Arrange a band listen. Highlight a few of his worst excesses, but be sure to include a few from others too. Make him feel part of a collective band improvement drive! Clever editing & presentation is the key. Hold all band members to their promise to clear out the clutter so the band can deliver a clean clear message. If he feels he's part of the solution, not part of the problem, you'll probably get your way.
If that fails, it's Bob's tractor I'm afraid.