No, early through mid-morning is a madhouse in the Wing. It depends on the arrival of the long-haul flights, but basically there is a massive transit bank longhaul to shorthaul that happens between approx 6am and 10am. Start time of rush hour fluctuates by 45 minutes due to seasons / daylight savings time / delays. But by 7:30am any time of year it is packed. Mon-Thursday are the worst, because you also have massive #s of ex-HKG O&D business travelers mixing in with the transit pax. Fridays better than Mon-Thurs, and weekends most pleasant.

Wing gets the biggest brunt of visitors it because it's next to the two largest transit areas, and also next to exit security / immigration for O&D pax. You never have to go out of your way to go to Wing while you do to Pier. So Wing is easier to predict: crowds more likely here than Pier.

You have another "rush" between 9pm and midnight as a bunch of Europe, and a few N. America + Oz departures leave then. However, this rush is less predictable because it really depends where the Europe departures are leaving from. If they're spread out all over the airport you may not notice it; pax will be spread between Wing, Pier, Qantas, Bridge, etc. If all the departures are all clumped together by the Pier, then the Pier (particularly Pier F) main lounge area gets completely overwhelmed, because it's too small for that many flights. However it's really hard to say. Normally Pier F is very pleasant and you don't have crowding issues, but you notice its small lounging size in a hurry if you get unlucky and there are 4-5x longhaul departures nearby. BA also has two latenight departures and their Emeralds / F pax can be in the F lounge and Sapphires / J class members in the J lounge. IME it really depends where the Europe departures are leaving from which determines the late night lounge crowding.

4-8pm is not rush hour.