There is some literature on the topic, e.g., AFS callbacks (later called "leases" in the NFS world) and Coda's variable- granularity callbacks... the problems aren't exactly the same, but it seems like there might well be an opportunity to learn from existing experience.
This describes experience gained from a system with actual users (i.e., isn't just a simulation study): Exploiting Weak Connectivity for Mobile File Access http://www.cs.cmu.edu/~coda/docdir/s15.pdf Dave Eckhardt
