G'day Sean,
Bill is right - the ASWA group is a good place to ask.
The dorms vary in size. There's 4. I think there are about 10 bunks in each, but to be honest I haven't been in them for many years as I have used alternative accommodation for some time now.
The dorms are sufficient, and not usually too noisy appart from the odd snorer. If you're going for the first time, they are the easiest way to stay there. The dorms, showers and toilets, and food/general hall are all close by and convenient.
Roger.