This segment may be longer than you desire for your trip, but on the LAX-BKK and JFK-BKK routes THAI runs a three-class A340-500 with 36" pitch 2-4-2 Economy, and 42" pitch 2-3-2 Premium Economy. Both are outstanding products that lead most other airlines in comfort. The Premium Economy has been costing $199 (one way) over Economy fares much of the year with promotions THAI has been running. The Premium Economy is much better than typical Domestic US First Class, and much appreciated on a 17 hour flight. I find it to be a superior alternative in value (at about $1500-$1750 RT) to the typical $5,500 RT cost of Business Class.