It's only 1000 miles (2000 miles with DEQM) difference, but instead of spending almost all of 36 consecutive hours on planes, I'd strongly suggest making SYD your final destination and foregoing a few extra miles.

Since it sounds like you are *G, you should either take some time to check out SYD or, as I did several days ago, just spend the time in the NZ Koru Club. It's far superior to any RCC and has showers, plenty of food and drink, and wireless internet. You also won't have to re-clear security aside from just passing through the metal detector to catch a "transit" flight - no need to deal with customs at all provided you're not checking any luggage.

The other suggestion is simply to stay on west coast time during your trip. It's easy enough on the outbound since it leaves late at night. Sleep for a few hours, then stay awake on the plane the rest of the trip and throughout your lounge visit. After boarding (it should be around 9 pm west coast time), stay awake for a while and then sleep overnight. Good to have an eye-mask since it'll be light outside when you first try to sleep.

If you're lucky, you might be able to get a row of seats to yourself. If that's the case, it's a breeze.