[@Red Wizard]

 I suppose it depends on how large of a group you prefer. Honestly, depending on the game the larger the group the harder it is to keep things flowing smoothly. Over the years when it came to collaborative writing small groups work best. Hell, even Dungeons and Dragons gets a big unattractive when the group is more than five or six. 

Your call. I think four or five would be perfect. Post a link to the OOC please?