[Brian]

We'll be making a change for upcoming builds that will give the database more opportunities to compact, even with a setup like you're using, Gary. Once we get those builds out the door, this should be less of an issue.

In the meantime, though, you can force a compaction. Make sure all your devices are up to date/synced, then do the following:

Open Sync prefs on one of your Macs.
Press "Show Clients".
Unregister all clients, even the one for the Mac you're doing this on.
Set sync method to "Nothing".
Restart OmniFocus. The "Compact Database" menu item will now be active.
Use it to compact your database.
Turn Sync back on and start a sync - you'll push the compacted database up to the server.

The next time you sync the other two devices, they may ask if you want to use the "Local" or "Server" database. It's very important that you answer Server.

Does that help?