Just done HKG-JFK return with CX, and having read this thread thought I'd comment. The 777 only has six F seats, which were all full on these sectors. I was able to select seats after registering for an AsiaMiles number, and could get the first row in J.
The service was very good, and I think used my name on both sectors (too much travelling to be sure). Not too sure I like their new J seat (ok when lying flat, but a but restrictive when upright)