That's a piece of advice I give commishes when they ask. If you have a standard of admission, don't go crazy if you can't fill immediately. Other owners will press you to get rolling but it takes 32 good owners to make a world and just one bad one to wreck it. Once you start a cycle of one and done owners on a team, it takes forever for that team to recover. And, by bringing in the one and dones, you'll frustrate your base owners.
Or worse, the bad owners will stay and the good ones will leave.