If I were doing this, I would:
- Use the Desktop PC as "the master" copy. So get your database set up properly there first.
- Before each use of the laptops for running tournaments, update the laptops with a copy of the master database. You can just copy the "db" folder from the desktop PC to the correct place on the laptops, or you can use the Backup and Restore features built into the software. Either will accomplish the same thing.
- When running tournaments on the laptops, definitely use players from the database, and add any new players to the database.
- After running a tournament on the laptop, copy the saved tournament file back to the Desktop PC. Open the tournament file, go to the Players tab, and press the "Add All to DB" button. This will add any new players to the master database.
The only issue I see is going to be getting player information changes (for existing players, not new players) from the laptops to the desktop PC. Since you're only adding new players to the database on the desktop PC, changes to existing players won't get propagated. You'll have to keep up with those manually.