It seems the AMS-HKG route is very full at the moment, have heard from soemone that a few days ago the KLM HKG flight was also very full. These are good loads for February!

Regarding check-in time, it may depend on the port, but I know some CX ports open 4 hours before departure, but someone wrote above that it is 3 hours for AMS, so not sure. However if your waiting around, it might be worth checking to see if they have opened at 4 hours prior to departure.