Savage25,
khop khun khrap for the tip! I managed to get 32C for both the 777 legs and I have to say that approximately 5 meters of leg room is a new personal record in economy.
Frankly, I think C is a better choice than A, because there's nothing but the hallway in front of you. The flip side is, of course, increased odds of getting your toes run over with a duty-free cart, but the staff were pretty careful. Oddly enough, the planes I flew on featured a telephone booth (!) next to the 32C, which was excellent because nobody ever used the thing, so no queues and no toilet smell either -- unlike 32C's evil twin 32H. And oh yes, no bawling infants on either flight, nor seatmates in 32B; was I just lucky? (32A was occupied.)
Unfortunately BKK-KIX overnight isn't the greatest of flights for sleeping. We left behind schedule at 2 AM (Japan time) but landed almost on time at 6:30, and with breakfast service starting a little past 5 AM (ack) it was theoretically possible to sleep a maximum of 3 hours or so, and despite the rather generous seat pitch described above the recline wasn't all that great. But the flight was full and that's what I get for flying Y... the return flight during the day was, in the end, probably more pleasant, partly thanks to a good book to kill the time.