Well I looked at the seating chart on UA connection and it is a 747-400. Matt Wald is right that row 15 is the absolute best. I just had that on my flight from IAD-FRA not so long ago. More leg room then even in First Class, unfortunately there is no window or side bin, but plenty of closet space as soon as you come up the stairs for carry-ons. The only other problem is that this is an Emergency Exit row, and therefore UA will only assign them to 1K and PremEx members in advance, but you can try day of departure (if you are not of either of these status). Right now all seats are wide open, except 12GH, which I assume is you, and 6AB and 7B. They do tend to have the new Business Class seat, with in-seat video, although your flight will only have short-subject.