Update sets are typically done on a dev instance. Once ready to promote to QA/test instance, and after testing there, they are promoted to the production instance. You set up the relationship in QA/test using the "Update Sources" module under "System Update Sets" to add the dev instance as a 'Remote instance'. Once done, you can open the 'Remote Instance' and on that form is a Related Link there named "Retrieve Completed Update Sets". That will pull any non-existent update set that is in the Completed state on the source instance. Preview and commit. And this is a manual process performed by an admin user. Working with update sets 'programmatically is not possible that I know of. See screenshot.
If you want to know when any table is changed, then you can create a business rule on sys_db_object and sys_dictionary, that notifies you via some Event defined. I suggest you post another question here on that. And on "to automatically create and destroy the Business Rule, even just using my existing ServiceNow module, ..."
