I'm curious what data points people have for Z (J-F) award ticket upgrade inventory opening. My partner and I are flying IAD-DXB (a380) in a few weeks. He was able to snag an UG to F 9 days ago when there were 9 open seats. There are still 8 open seats, and I'm constantly checking the app. Do people see Z inventory appear at given points, such as 14 days prior?

I have already upgraded my onward leg to BKK, so it sounds like I should call to upgrade the IAD-DXB leg to get a lower total miles upgrade for the entire trip vs. redeeming the miles quoted for the IAD-DXB leg once it becomes available?