I did the opposite trip a few years back. Only three of us on a Davidson 55 out of Gladstone QLD. One of the guys had circumnavigated the globe professionaly, so I felt pretty comfy.
I would have a chat to a few of the old salts around the sailing club and see if you cant pick up someone with some experience to assist. Not that its a hard trip but its good to have that extra experience on board.
We did Gladstone to
Auckland in ten days. What is your
destination in OZ?