thanks for your response. Yes, I would hate to be stuck in the middle seat of the 252 configuration on a 777. But so far, I have managed to prebook my seats and have had either aisle or window. Once I was assigned a seat in the middle on UA from SFO to CDG. But they managed to change it a few minutes before boarding to a window seat, phew !
I prefer the seating configuration on 767 too. Unless of course they change the seating configuration on 777 to 333.
So, not all of their 767s have PTV ?