Well, it turns out 6 months later to be just as I was expecting. The shutter doesn't close dependably again. I remember that the shutter-return (shutter close) spring just doesn't have the strength to do the job. I remember it didn't hardly have enough strength to move its own self, much less the lever that it's supposed to move. I've gotten hold of some music wire and am going to proceed with fabricating a new spring. As it turns out, an internet search to freshen up on spring fabrication and tempering turned up my own thread.
And I'm going to get all that graphite out of it I slathered it with, as I think it was a dumb idea on my part.