VK6 and VK8 are in zone 29 with a decent number of active hams. You may also find stations in Antarctica in zone 29 (as well as zones 12, 13, 30, 32, 38 and 39 which all come together at the south pole.)
A VK6 is a lot easier to work than a VK8 from the East Coast of the USA. VK6 has areas on the ocean and can be worked long path on 20 meters during our late afternoon and if conditions are good it can be worked again around 0600Z and at our sunrise. Perth is the largest city in WA, or VK6, with a population of 1.8 million. I've worked many stations from VK6 in 25 years.
VK8 is in the Northern Territory and although it comprises a very large area the total population is less than 250,000 which is about 1% of the population of Australia. I believe Darwin is the biggest city in the NT but it only has a population of about 130,000. I don't believe I have ever worked a station from Darwin. I have worked stations from Alice Springs in VK8. Alice Springs was home to a joint US/Australian eavesdropping post during the Cold War but I don't know if it still exists. It also served as a relay station for Apollo moon missions. I watched an interesting movie about the relay station which one would think few producers would want to make giving the dry subject matter but I found the movie quite good. No doubt my radio interest was a factor in my enjoying the film but I don't think one would make a film which just appealed to radio enthusiasts.
73,
Chris/NU1O