As a OW Emerald, I've gotten F all but ONE time that I've flown HKG-DPS (or the reverse) with three-class equipment. The upgrade was automatic... no requesting on my part. The one time I did not get it, I'm 99% certain that those who did were all Marco Polo elites. But on that one flight, the FAs, came around to bring me champagne prior to departure (not with the other J class folks) and took my meal/drink order before the rest of the cabin... when someone else complained they told them "well, she SHOULD be up in the next cabin so we are treating her as such". I had said nothing, but in that way that CX has, the staff just "knew". So I'd say "don't sweat it, they will take care of you".

(Says she who is about to fly in Y on Dragonair HKG-HKT in a couple of hours... *cringe*)