Since I'm here, OOC, is there a maximum recommended number of files to sync over Ethernet at any given time.

No. If you're using the latest software, large synchs should be fine. The only thing you'd want to worry about is if the power goes out or Windows craps out on you mid-synch. For that reason, you'd want to do it in smaller batches so you don't have to re-do a bunch of work if something bad happens. But emplode/player should be good for big synchs at this point.