The idea is to work without leaders, so it wouldn't feel right to have quotas or deadlines that the group hasn't set for itself. In any case, this is the first project of its kind. Let's focus on finishing the work before we try and break any speed records.
Think of it as a project that will be completed no matter what you do. You don't have to worry about the whole thing folding up. Instead you should concentrate on making a contribution and ensuring that you're still here at the finish.
As for future swarms, I can see them having HR meetings. Everyone will have some idea of how much everyone else is contributing. If someone is slacking, they risk getting voted off the island, losing half their share, and not being invited to future collaborations. On the other hand, the really hardworking artists will be free to find groups that more closely match their skill level and work ethic.
Basically the swarm exists to help each of its members. But it's not a free ride and it's not a drag either.