While I don't dissuade you from J, if it is only due to your height, Qantas does sell exit row seats for around $150 per flight, they'd likely suffice and assist in the height concerns, but otherwise, it is a very long flight. Qantas IFE is really great and the Economy food service is much better than that of US carriers. LAX to BNE on Qantas Economy was much better than NRT-DFW on AA; those are the only two times I flew economy overseas.