[whpalmer4]

To open a database other than the "production" one, just double-click the file in the Finder. OmniFocus will open it in a different window, and you can interact with it much like you do the "production" database, though perspectives won't work. If you need to restore a project or some actions, you can just drag and drop them into your database from the other window. No need to move any files around.

Do not use File→Revert to Database Backup for this purpose! You want to look at the old database, not revert to it.