Just downloaded it, but haven't tried it yet.
Although a backup is Always handy, just remember that FM2006 can pick up the database from alternative locations as explained here:
http://www.sigames.com/sibase.php?type=view&id=166
Specially consider absolute paths (6.0.2 onwards only) as:
--database_location="/c:/my database/test update"
--user_data_location=<folder>
So, there is no need to overwrite the original database, a simple C

ThirdPartyDbs folder with subfolders for each version or test database is enough.
Nice work.