There's a great article on ProSound Web (which also runs a few of my articles too) that's an excerpt from his great book, "Make Mine Music." Bruce also was kind enough to contribute an interview in one of my books as well - The Mixing Engineer's Handbook.
Below is an excerpt from the article over on Prosoundweb.com, from which I took some of his points about vocal recording.
- When recording vocal duets, I frequently look for microphones for the vocalists that have an obviously different sonic character. This difference in microphone character adds to the already different timbre of the two voices and makes the resulting sonic picture more fascinating.