Need SWU advice DFW-LHR
I have trip coming up DFW-LHR may 5, returning may 12th. Of course no Y-J UPG available at booking, so what are peoples advice about getting it. They have 3 flights using 77W, 772, 763. Of course the most J seats are available on the 77W but this is also the best plane of the 3 so may get sold. Am I better booking on one of the other 2 planes as far as SWU eventually clearing? Thanks for the help.