Training referral for multisite network administration

Do you all have any suggestions for training for advanced multisite network administration. We have a university implementation of multisite and our primary admins are very experienced web server/app admins but new to WordPress. We've been working with it for some time but are looking for best practices for security, performance, etc. I imagine we're doing a pretty good job already, using WordFence etc. but have not had the benefit of advice from experts. (We're not currently interested in development of themes or plugins but that seems to be the primary training out there.)