I agree; Y is oversold, and I'd say your chances look decent at this point. They're currently selling J6 C5 D0 Y1 B1 M1 E0. That means they're likely oversold by 10 in Y, and are willing to oversell by one more. That's good for you, because the seats that they're blocking from inventory can't be sold as upgrades during check-in. As things currently sit, there will be at least 10 upgrades.
You should be first in line out of the Gold passengers, so the question is simply how many GS, 1K, and Platinum passengers are ahead of you with waitlisted instruments. There's no way to know that, but I certainly like your chances better today than I did when you first posted.
