I have used both types - the HSS drill and the small holesaw style.
By far the easiest (and best results IMHO) is the 8mm HSS item (below). I think they're actually a milling machine bit but they work a treat.

I get mine from Gasweld on Research Rd @ Pooraka. Cost around $15ea although they did not have any last time I enquired.
Also try KC tools on South Rd @ Wingfield.