1. What are your experiences with it?
2. How well has it/did it work for you?
3. What were your techniques?
4. How did you and your co-author handle characters?
5. How much plotting did you do together before starting to write?
6. How did you handle chapters/scenes? Did you each write a chapter then send it to the other person, or did you each write a scene and send it to the other person?
I think those are the only questions I can think of.
I ask because I found someone at a message board for writers to co-write with, and neither of us have ever tried doing it before. We've started doing a little plotting but not a ton, and I wanted to see what other people's experiences with it are.
Cross posted to several communities.