I hope you can bear another waitlist question. But, being my first year as a 1K, this is my first intl. waitlist (got lucky on last two flights to SYD...got upgrades both times at booking).

I’m flying SNA-SFO-NRT-BKK next Wed., 11/16. Returning BKK-NRT-LAX-SNA on Tues., 11/22. Got the SNA-SFO upgrade at booking, waitlist came thru a few days ago on the NRT-LAX return. But still waiting on SFO-NRT and NRT-BKK on the outbound, and BKK-NRT on the return.

Yes, I’ve already done several searches, and have found out some good info:
1. Odds are better on transpac to/from NRT flights.
2. Much better odds flying mid-week (when I’ll be flying) than on weekends.
3. These flights have a relatively high rate of last minute premium fare bookings.
4. UA seems to be doing more last-minute upgrading this year.

Still, perhaps some savvy travelers who fly this route frequently can fill in some additional details...specifically:
1. These flights seem to be fairly wide open in the C cabin…approx. 50 C seats still available on the transpac segments, 24-34 on the BKK segments. I might understand holding back seats on the BKK segments, but not upgrading on the SFO-NRT segment? But...does United seriously believe that they’ll sell 2/3 of their entire C cabin (51 out of 73 seats) in the next 4 days???
2. Any guesses when they might move some upgrades? Day before flight? Sooner? Might they hold back until the DM list at the airport? Several agents said that my chances were excellent. I’m on PA waitlist, small waitlist, and lots of open seats. Yet I’ve gotta wonder...if my odds are so strong, why hasn’t there been any movement?
3. If there’s no movement on the outbound, can I drop the SNA-SFO upgrade (or convert to 500 Milers)? I don’t want to burn an SWU on a lousy 1 hour domestic flight.

Thanks for any help or suggestions!