Wondering about my chances: I'm booked in W for LHR-SFO UA 939 on 9/11, Plus Points upgrade by a friend, so I have no status. I'm seeing 18 open seats in J with a little less than a month to go. Sounds like a lot of open seats, but I don't know how busy this route gets closer to departure or how many upgrade requests, considering I'm probably at the bottom in priority. Chances of clearing?