@Lady Well the Slack workspace I'm in most often has 711, but that does feel like too many. I think it scales with the number of people? I would probably say eight or so top-level would be the max in general unless you've got a ton of people. And to go with it, probably not more than eight in each top level category (with the same caveat).
@Lady the forum i used the most had surprisingly few (and also in typical fashion we mostly just used /genran)
we probably need some more