2 to 3 characters per creator is fine.. Big characters go in the back (further down the beach).
I'll start us out (in another, more official post) with a psd (photoshop) file saved on dropbox. Each creator will have an hour to place their own character in the scene, re-save the psd file to dropbox, post the dropbox link and post the updated pic.. We had a line form last time, the creator would just call out if they wanted it to go next to avoid double savesies..
It worked out pretty good for our first try at it.