I think if anyone says they know the answer they're probably lying, as if it's not there, no one except the faculty know and that's a secret kept by them.
I think those kind of weightings are kept a secret, but I'd presume it's fairly equal by the sounds of things.
But then again, I ask the question: who cares? I mean you know your UAI but you don't know how it compares to other applicants, you know your UMAT but you don't really know compared to other applicants to that uni (except from previous years) and you really can't say about your interview. So don't worry, do your best and wait for offers.
Keen