[botsrmyonlylife]

Our team used Slack last season and it worked really well and we are planning on using it this year. At least for me the most difficult thing was adjusting to using it but besides that it has been great. Now to your questions....
1. We have Slack set up for subgroups/projects and for social media/other things we use such as github and asana. We have a general channel which is the main channel and we have a random channel for random stuff and articles that are cool/funny.
2. We don't have any explicit guidelines just general be nice, don't post random stuff and check often.
3. We have 20/30 members registered on Slack.
4.It has worked great. We made a mistake for having too many useless channels. Just have ones you need and have a way to organize yourself so you are all on the same page.
5. Don't put too many channels, use private channels if needed if only a small group of people ned to know (we have a private channel for leadership), add integrations but not too many, archive channels you don't use. Good Luck!