Now, I might be beating a dead horse here, probably one that has been dead and decomposing for a while now, but I'll try it anyway.
There have been plenty of discussions about the new graduation mechanics, and the most controversial one is that the higher privilege levels that come with graduation are still coupled to the design.
The privilege levels are one of the graduation aspects that I think is the easiest to tie to objective measurements. The reputation required for actions like closing should be elevated to the graduation levels once a site has enough active users at the elevated levels to ensure efficient moderation.
I suggest to just tie the elevated privilege levels to a certain number of recently active users above 3k reputation. Closing is the single most important community moderation privilege just behind editing. I'm ignoring deletion as this can be handled by diamond moderators for smaller sites. Editing should be covered by the number of 3k users as well as the requirements are lower than for closing.
I'm not proposing any hard number, that should be done by evaluating all the existing successful betas, but I'd estimate something like ~15-20 users at 3k+ that have been active in the last month. Enough to handle most closings by the community without the diamond moderators.
Elevating the privileges too early is problematic, I still remember Gaming which had a period just after graduation where you needed pretty much every 3k+ user just to close a question without moderators. I think this is one of the graduation aspects that is suited best for an objective threshold, there isn't much debate necessary, either a site has enough active 3k+ users or it doesn't.