Do they use the single finger in Australia or the two-fingered equivalent?

It seems to me that the two-finger version is much easier to do - giving someone the single finger involves trapping the first finger with the thumb, so it doesn't fly out as well. I find that to be quite a tricky manoeuvre. I think that's a good reason for preferring the reverse v-sign in moments of high indignation. But of course it's no good if people don't understand it.