Wanted to follow up if anyone is interested.

Called in to EK, they tried to force me 2:30-3:00 car in advance. I know HKG and timings very well and had no desire to sit in the lounge for an hour or two. After some negotiating, EK agreed to arrange my driver 2:00 in advance provided I verbally told them on the phone "I accept the risk" of potentially missing my flight. (I arranged 5:50am for a 7:50am flight)

Then, a day before the car company called me. I asked them to push it back again, to pick me up at 6:00am instead of 5:50; no problem and no negotiating needed. (We live on HK Island, drive to airport with no traffic at that hour is about 35-40 minutes tops. Could be 30+ if driver is aggressive. I presume the car company knew my request wasn't an issue.)

Day of flight, the car company arrived a few minutes early around 5:55am. We left at 6:00am. S Class Mercedes and professional driver. EK had a rep waiting for me curbside upon arrival at HKG. Overall solid experience and much better than my other CD experiences in DXB and a few European ports, not to mention much better than my last arriving-at HKG experience. I had actually just booked my own car my last two ex-HKG flights after lackluster experiences with CD before. So this was a nice change of pace!

My main concern was not having to be picked up at an ungodly hour and then be forced to sit in the lounge for an hour or two. That was avoided and I'm a happy camper. The S Class was good too and comfortable.