QUESTION:  I need some strategies for pragmatically added/removing users and programmically managing their roles from an external exe.   

More Info:  I need to manage user access and roles according to information found in a external system.  Here are most of the business rules:

• This will be a system with a main root portal and sub portals.  The same users will exist across all portals.
• All users have access to the main root portal.
• Access to the sub portals is regulated by information found in an external system.  
• I would like this to be an external program that will run nightly as a  local EXE windows app.

At night a program would run and add/remove/modify DNN user access and roles according to the external accounting system.  

What interface level is good for this: Is it best to call the stored procedures or access the libraries?

Much thanks,

Terry