Dan, as a Platinum or Gold Elite you should be able to score two WBC seats at the standard level with some advance planning and flexibility. I think Platinum and Gold Elites have the same extra availibility, Silver Elites and regular members do not have this bonus.

I'd opt for Bangkok. You don't say where you are flying from, but if you originate or connect in Detroit, Minneapolis, or Los Angeles you will fly a 747-400 from the US to Tokyo, and then connect to an Airbus 330-200. The Airbus is a little cramped even in WBC, but it is new. I much prefer the 747-400. WBC is a very good product and the seats are excellent.

Booking eight months in advance for WBC award travel to Bangkok is not too early, and you may still have to be flexible. I booked my WBC award tickets to Bangkok 352 days ahead at 12 midnight, just as soon as they were released. Using this method, I was always successful as a Platinum or Gold Elite. Now that I am just a lowly Silver Elite, nothing is available even at the 352 day window.

You are correct in that upstairs is the way to go. I think seats 73A & 73B are the best, you can reserve them 90 days prior to departure.

Bangkok (and Thailand in general - Phuket, Hua Hin, etc) is a great destination, and will certainly fit as a "trip of a lifetime" to combine with flying on the upper deck of a 747.

Good luck and have fun.