The flight to Los Angeles can either be BKK-NRT-LAX or BKK-KIX-LAX depending on day of week. The flight is operated by B747-400 on both sectors. The seating is still old first class (18 seats) so my favourite seats is row 2 aisle. (2B or 2J). And if you don't care about the movie, try 1A and 1K which gives good legroom and privacy (but can't see the movie screen).