You can definitely use an event-based pattern. C# has its own event type that Normcore uses for all models. If you check out the Synchronizing Custom Data guide, you can see I use this same pattern to avoid updating things in Update().
Maximum number of players is really tough. It depends heavily on how much data you’re trying to synchronize. Typically VR players with voice chat, you can get 4-8 players per room on Normcore Public before the server hits CPU limits we have in place. On Normcore Private you can remove these limits and get to about 80 avatars with voice chat before you hit CPU/GPU limits on the Oculus Quest.
Max