Adam
Been thinking a bit about this and for what its worth here are my suggestion:

if User has role Administrator or SuperUser then
    Use Admin_... settings
elseif (User has Role specified as an editor for module) AND (Role has settings in config)
    Use Specific Role settings
elseif User has Registered User role then
    Use Registered_... settings
else
    Use Guest_... settings
End

The problem with the above is that if there is more than 1 Role (other than Admin/SuperUser) specified as an editor for a module a conflict could occur.  However, on the other side looking through our portals we don't have any modules with more than 1 Editor role.

Any way my 2 cents

Antony