Which settings overwrite which? If I remember correctly the database settings overwrite the settings.php right? Pretty much I have multiple forums that I want to use identical configurations (except for site specific settings like URL, cookies, etc...) and want to figure out the easiest way to configure those settings.
Yeah the settings.php is just a copy of the database. If you change anything in the settings.php you will need to change it in the ACP/Database too otherwise the changes will be lost :p
The forum uses settings.php. Whatever is in there will be what's used. Saving the settings in the ACP updates the database which then rebuilds settings.php, but it will use settings.php on the forums.