I applied in April 07, but I'm in Melbourne. That probably makes a difference. Online tests were done in July and assessment day in December. Interviews in Melbourne are in 2 wks time. I had trouble being patient with that timeline, I'd have trouble if I'd waited all this time since doing the actual assessment day 9 months ago.
To answer your question, for every test you get to spend a fair while practicing and the instructor spends a fair while explaining each test, just so everyone is in no doubt what the tests are. If anyone's in any doubt after the practice tests, they shouldn't be an ATC
For the arithmetic test, you only get about 5 sample questions I think.
But for the simulated ATC test at the end you get about 5 practice turns, each about 15-20 minutes long.
Between each test, you get a 10 minute break while the instructors set up the computers for the next one.
And that's why it takes about 8 hrs. You do get results with half an hour of finishing though.