This is not a job that will get you "on to their twins" in 6 months or ever for that matter (historically)
The Roams survey project is almost a completely seperate entity to the rest of the company. Go there, get some experience traveling aus doing survey, have a great time and then go north and get a job with Hardys, Chartair, hinterland or west wing and learn to be a professional pilot. You will not fly a twin for them and it's a lie if they tell you otherwise. People have spent years there and left because that magic twin in Melbourne never came.
Still amazes me the amount of people who think they can work somewhere for 6 months and are entitled to a Twin job on the east coast