Follow-up: since I wasn't seeing anything about being waitlisted on united.com, I decided to call UA just to confirm that I was indeed on the waitlist for the upgrade. Of course, the first time I tried I was hit by the computer outage...

But the second time I called (after watching the ORD staff finally be able to log into their systems), the helpful res agent looked up my flight; I could tell right away that I was NOT in fact on the waitlist just listening to her.

The good news is, she said, "Oh, you're using miles, right? I can go ahead and confirm you in business on UA 6 ... here's your seat assignment." SO now I will indeed get to try out p.s. business Good thing I called back in since the original agent apparently didn't know how to either handle upgrades with miles or even to put me on the waitlist.