Originally Posted by
anabolism
I don't mean to imply that there's anything wrong with applying the SWU to the domestic connection and hoping the international leg clears. It's your SWU and your call. The alternate method is a hassle, so I can understand not wanting to do it. If this was my last SWU ever, I'd want to be sure I used it for something worthwhile,
but everyone has their own tolerances and valuations.
Also, it gives it a better chance to clear. It's entirely possible that there is never any upgrade space available and the only way to get upgraded is at the gate.
FWIW I'm totally willing to cancel while at the gate if my upgrade doesn't clear for a sufficiently long flight. It's not even a close decision. I would rather not go then fly economy for 15 hours.
Anyway it turned out that I found upgrade space in both directions on one round trip (to ICN). So that's booked and the upgrades have cleared. Basic econ fare was $930 so, not a bad deal with the SWUs.