I have come across this, it kinda sucks in a way, as they hold the "owner" of the car liable for the mods on the vehicle, yet if you ring QT (Queensland Transport) "before" doing the mods, they don't help you much, just point you in the direction of a place that does blue plates.
So finding out the info yourself is difficult, the people who make the rules (QT) wont explain them to you, so you have to place all your trust in a engineer licenced by QT, but then QT wont stand by his/her decisions/interpritations of the rules if they don't agree, and the owner is still left holding the responsibility to fix it.
Clearer rules , firmer or not, are going to be better for everyone !
So would it be a safe bet to be ordering my 33s yet David ?