This is some years ago:
2 Crews operated on the aircraft, an 'A' crew and a 'B' crew. The nominated Captain was the 'A' crew Captain. The 'B' crew was effectively the backup crew.
The 'A' crew flew DXB - SYD/MEL had 38 hours off and then operated as the 'A' crew back to DXB with a different 'B' crew.
The 'B' crew had 24 hours off in SYD/MEL and then operated one sector as a command crew SYD/MEL - AKL/CHC.
Another 24 hours off and operated back to SYD/MEL.
Another 24 hours off and then operated as a 'B' crew with a different 'A' crew back to DXB.
I found operating as a 'B' crew meant undesirable crew rest times on the long haul sectors, with the added NZ sectors contributing to some jet lag on arrival back in DXB.
Operating as an 'A' crew meant reasonable crew rest times, plus a single long stay (38 hrs) in SYD/MEL and then straight back to DXB with very little jet lag.
Not sure how it works now, given the increase in frequency of services to Australian ports.