Seatguru.com is a great resource in general. I agree with those suggesting trying to buy either a first-class seat or two coach seats. I realize this may not be possible but if it is I think it's really something that should be considered. The advantage of first-class seat is somewhat wider seats and generally considerably more legroom. The advantage of two coach seats is a much wider seating area. However, two coach seats will have obviously the same legroom as a single coach seat. One thing that is critical to be aware of, however, is that some seats in coach (and virtually all in first) do not have an armrest that can be lifted. In this case two seats isn't going to help a lot, although it will help a little with shoulder room. Whether the armrest lifts up or not will vary from plane to plane and even seat to seat in some planes. In general, SeatGuru.com will describe whether the armrest is moveable for a particular seat on a given plane. It would probably be good to discuss this with the airline as well.