Thanks everyone for the feedback. I called UA again and found a flight. SFO>HKG on a Monday no less. Who knew.

I also think they are working hard to make you buy the ticket without a confirmed upgrade. Kept pushing me and telling me it will be a good chance, etc etc.

How do you guys search for R class on routes btw? Is there a search engine or just have to call United and ask? sorry for newbie question.