The current setup for the university I'm at is to have multiple sites to support the different campuses (in four different states). Our regionals have a smaller Apple footprint so they all fall under one site each but our main campus has three sites dedicated to it (IT Security, Academic, Staff) due to a larger Apple deployment. Out of the 20 accounts and users of JAMF Casper Suite, only 6 have Full JSS Admin rights while the rest are segmented to their own sites (rights on sites depends on managers desires). The only policies that are pushed globally are passcode/FileVault 2 requirements dictated by our IT Security group and emergency security patches which are also dictated by our IT Security group.
For staffing, it depends on your orgs layout. We have our admins at our main campus and techs at the regionals. The regionals really only troubleshoot issues and when in doubt they reimage it (mostly lab setups) and our admins at our main campus will build out/test new images, packages, software before rolling it out.
For organizing everything by site, building, department you can pre make the groups and then move everything where you want it. It's super helpful for inventory and when someone ask how many assets are in this building? Although, something to remember is all buildings and departments you enter will show up in every site. We try to mitigate this by using region codes so no one mixes up buildings (academia likes to name buildings the same thing on multiple campuses).
Hope this helps!
