Have done that flight a few times and echo what other have said re the next day arrival when flying HNL/SYD as Hawaii is 20 hours behind SYD in July as it won't be daylight saving then.
For the SYD/HNL flight on the way over you arrive the same day as you're crossing the international date line so even if you depart SYD on Sat 29 Apr in the evening, you'll arrive same day in the morning.