So far we have gotten 3 of 4 transpacs on non-upgradable fares op-uped. The 4th one SFO-NRT was a doozy, I had the aisle 41G but 41F was a 300 lbs. guy and the two of us had to sit in "staggered" formation. Up in C there were 30 open seats. It really made me question my sanity purchasing "K" fares. But then the SIN-NRT flights were very open, maybe 40% full in E+ so that was easy. Got the op-up today on the way back NRT-LAX.

Basically you need high status on a flight with full Y and spare room in C/F.

Got two more to go next week. fingers crossed.