I keep the warmest spot at 30 - 35 C. The cool end is around 25. A 'heat gun' type thermometer is very handy because it measures the temp where your snake is sitting, not just the air.
I prefer the ceramic heat emitters and have found that they have a very long life. You need a light cage around any heat source or light. We use compact flourescent globes for light.
At first I only used daytime heat, but I was unhappy with the night temperature drops during cool weather in Sydney. You will probably have the same in Victoria. If you want a controlled temperature drop at night, you can buy a Habistat day/night thermostat. I have those in all enclosures now, but used a normal probe thermostat and constant temperature for 4 years with my spotted and stimson. Once you get the enclosure right, they are very easy to keep. Even though they are supposed to be ground-dwelling, my spotted loves to crawl along a branch. He is very active in the evenings and fun to watch.
I get my thermostats, light cages, etc from Herpshop. They aren't shipping for a couple of weeks over Christmas, but it's worth waiting.