Over at the Buckethead forum, they do DVD 'trees' a lot. (I usually just do straight trades, but I'm familiar with the tree way) Usually people will put down the names of all those participating, starting with the first people, and then the 'branches' that follow. I think since this is going to be smaller scale, just doing it by PM will be fine. I'm one of those on the first mailings, so when I get it, I'll let people know and they can PM me. No need to get ahead of ourselves yet.