1] work on everything together, giving each other real-time feedback
2] divide up the song, each person editing only his/her part (but with betaing from the other)
3] leave everything up for grabs; each person claims a chunk when he/she gets an idea for it
4] something else?
And if it's #1, is it possible to pull it off without physically being in the same room?
How do you deal with, er, "creative differences"?

I haven't really worked on any (non-MEP) collabs since krzT and I made this video in 2004. We started by sitting down side by side and editing it together, which was cool but slow going. Betaing each other's work in real time, there's a tendency to want to perfect everything as you go along. So I guess it was hard for us to just throw something onto the timeline and go back to revise it later (whereas I'd have no problem doing that if I were editing alone).
After that initial burst of editing, we decided to just add to the project separately whenever inspiration hit. We made identical rips of the source material so that we could just pass the project file back and forth over the internet. This is a nice system because you get to build off of each other as the project grows, and it's possible to keep a history of the changes. But since Premiere doesn't have a "merge" option, we could only add to the project one at a time. It also potentially makes things hard when two people have ideas for the same section.
We did another video together, EPYC, but since it's structured like a MEP with separate "tracks" that we didn't really collaborate on, it's not exactly the type of collab that I'm asking about.
So, when you're making one video with one or more other editors, how do you make things work?
EDIT: attached an actual poll to this thread.
