The QR Check-In staffer told me early morning/late night were manic. A bit vague, I know. In many cases its pot luck. I was told by the same staffer that its the late night/early morning Chinese flights that, in her words, "cause most chaos". I have personally have found that departing on the evening EY flight around 8pm - its very busy as was my 8am departure on QR a few weeks back.
Inbound, I have generally been lucky, whenever I have arrived.
My experience is based on literally dozens of visits to HKT BUT the new airport has a unique set of understaffing/IT equipment issues which preclude it operating at optimum throughput capacity, for now.