John,
Are these for Global app settings such as web server port number etc.? If so, do you need them threaded? You should be able to set them to non threaded, then read them using X-Files upon app startup to set the Global variables that will affect the app as a whole.
But if you are talking about user preference setting for each person that logs into your web app, then that is far better handled as extra fields within your user table.
Cheers,
Devan