Sounds like you have done your research well. My strategy has been to never let my bike out of sight, which is not always possible unfortunately. When I do have to leave my locked bike, I try to select a place that has something secure to lock to. Not all bike racks are secure. I use a D-lock and a 10 mm cable to secure both frame and wheels. If possible, check the local theft statistics and avoid hot spots. Some areas in my town have had theft teams with both spotters and cutters. Also, try to lock up next to a bike that looks nicer than yours, especially if it is not locked as securely.
I wouldn't have thought that NZ would have a bike theft problem, but I just Googled and was much dismayed. Good luck to you.