Fred TinyMCE default configuration

The default configuration is hardcoded in the initialization. Is there any way to use a system setting to override this? If you create a custom configuration, does that have to be specified in every HTML element that uses the rte? I saw something in the fredtinymce.class.php code about
* Get a local configuration option or a namespaced system setting by key.
but nothing about how to go about doing such a thing, or exactly what settings or options are possible.