Data point: I have two RTs on ANA that are GPU eligible Y-to-C, but (a few months out) none of the 4 longhaul segments show space available using United's webpage for requesting ANA upgrades. This is despite united.com showing J9 C9....

Is the advice below from the wiki still applicable? That is, one should start checking more frequently about 2-3 weeks before departure? I don't have an account with EF (though maybe I'll think about it).

"* There seems to be mixed opinion on whether O and I class inventory is put back into the system as the flight gets closer, but several have reported finding inventory show up 2-3 weeks before the flight."