We used django-dbpreferences to store some setting into the database.
You can edit the preferences into the django admin panel under:
Every site has his own preferences. You can easy filter by site on the right content block.
Stettings are not changed, if at Lastupdateby is (None).
To get the defaults again, you can easily delete the entry (or all entries). PyLucid automatically generates the entries with the default settings, on first use.