Done! Life is good.
The lampshade fits. The lamp works properly. Of course, I had to watch that YouTube video three more times.....it's so hard to visualize knots.
Now the bad news is that I have to go clean up a bunch of little milk glass chips off the dining room table. The old milk glass chipped very easily where it connected up with metal parts.
But the good news is that I watched the Sklar Brothers's new You're Doing It Wrong video on YouTube today, too--and it's about how to clean up broken glass. Problem solved.
You're Doing It Wrong: