Even as a Platinum flying on a revenue business class seat, I had to actually call customer service to get seat assigned. You cannot do this on the website until 24 hrs before departure. They also reserve a set number for airport release so even as a top tier elite flying on revenue fares, I had to go to the airport a few times to get seats assigned on International J.

If you're flying business, I recommend Window seats - It is a herring bone configuration 4 across (narrow and angled but sufficient length). Not sure of coach seating on wide body aircraft.