I'm a pretty savvy user of computers and AC, but I have some questions regarding synchronization between multiple computers. In particular, I am curious to know
(1) How long other users' "synchronizations" take on average (including and excluding the pre-synch backup)? My "Imported Items" folder is pretty enormous, alas, and so the compression stage of the backup seems to take forever, making the synch (including backup) take forever, too. I should add, too, that the size of the "Imported Items" folder prohibits including them in the offsite backup.

Is this common?
(2) Can anyone (perhaps an AC employee) tell me just how savvy and robust the synchronization's algorithm is? For example, when it copies data from one computer to the other, does it copy only the data that's changed (i.e., detect files on the destination computer that are the same on the source computer and don't need to be copied) or does it simply copy over all data? As another example, can it handle changes being made to both computers? In other words, if I run the synch from the "server" computer to the "offsite" computer, then I make (non-overlapping) changes to each computer's database, then re-run the synchronization from the "offsite" to the "server," will I end up with a single, integral, healthy database that includes all of the changes?
Thank you for your help!