Completed a full sync against a single peer. This verifies the database sizing calculations, all chain object deserializations, and full sync shutdown cost. This was a single run for the whole chain against a single peer. That provides a good baseline for RAM usage for the memory maps.
My machine held the process private bytes to almost exactly 1GB. This flushed to disk in 5 minutes, with cost-per-file appearing roughly proportional to file size. The final store size, headers and bodies, at 781,877 blocks is 426.73GB.