Fair point. Let's assume that the only goal is to make the project go forward. All compensation and credit should be structured to further this goal.

I guess 100% is the best way to structure it. Possibly even with a disclaimer saying the founder would not create any company out of the source code - but could be hired by anyone who does. The founder's role would then, simply, be an evangelist for the project(s).

I think the last four people would participate in the hopes of entering the top six, but a more open plan would probably encourage more participation. I think the last four would participate with the goal of entering the top 6, just like the dozens of applicants for the winner-take-all Ansari X-Prize.