From a user's perspective I'd work much like you describe, yes. You'd start WeiDU and it would not prompt for your password and would run as a user process (i.e., with no elevated rights). If there were invalid pids, WeiDU would ask you to re-run as admin and exit. If there were any auto-updates carried out, WeiDU would say it was successful and exit (please re-run to install your mod). This I have to do to relinquish elevation for the remainder of the process (which does not normally require elevation, and running elevated with no need is a bad idea). This would also mean that unelevated WeiDU would needlessly exit if there were any auto-updates, but I deem this preferable to the alternative of needlessly running with elevation. If you were determined to install with elevation, you could do so by running as admin until auto-update makes no changes, in which case WeiDU would proceed with elevated rights.