Well i dont know how much use this would be to you guys since i applied for early entry in 2003 i think.
my trial marks were absolutely shocking...
one in particular was adv english with 49% (the teacher is to blame, class avg was low but we all did good in hsc). I did do 4 unit maths however... but wasnt that great either.
Anyways i applied for early entry for 3 courses and got them all except one was conditional that i get >50% for adv english
my interview consisted of just basic questions like y u like a particular subjects etc...
they do look through your porfolio though... mine had my resume in there and listed some academic achievements which i can assure you is a plus... school president, number 1 chess player, best & fairest, whateva... they all work to your advantage in these interviews...
they only skim through ur marks BUT do take notice. Its all about how passionate you are about ur career...
like any interview, doesnt matta how good u are pratical (unless it clearly shows ur top of ur class), its how you sell urself in the interview.