Pre-Syncing for a faster Field Level Merge experience.
The first time a database is synced with field level merge turned on, GoZync needs to initialize the merge database (called "zyncdb"). This is just a FileMaker table in GoZyncMobile, but it can take a while to initialize.
So you may want to make this first sync on your desktop rather than force your users to do it on their mobile devices over potentially slower connections (and with obviously slower processors).
If you are using filters, you'll want to temporarily turn them off for this seeding--the easiest way is to add an ExitScript line in the script "Filter Records to Pull" in your hosted file, right after the first "Show all records" script step. (Just be sure to remove this line after you're done seeding.)
What this will do is put ALL records (not just filtered records) in the mobile files and seed the zync database with a change state for all records. Then, when a mobile user gets the file and syncs with filters turned on (you removed that ExitScript line, right?) GoZync will just pull the records that match the users filter--deleting those records (and those zync db records) that don't apply to this user.
These deletes are screaming fast compared to having mobile users initialize the zync db on their own.
For seeding in GoZync 5.08 or later, there's a small change you'll need to make in GoZyncMobile. In the "Send File(s) Up To GZH" script, disable or delete the Perform Script step for "Clear Last Time Zync - Whole File". That will ensure your pre-sync is remembered when mobile users run their first sync.