Ab initios have gone to Cairns and Mackay recently, they'd be near the top of my list if I had a choice
If the instructors have a say, you'll go to a tower where you're most suited out of the choices presented to them. So if you're suited to metro D, they'll try to send you to one of those, Radar, they'll try to send you to one of those. The instructors do at least consider your preferences.
Unfortunately, it seems that just lately the only people with any say in postings are the pen pushers in Canberra. Your name just gets pulled out of a hat