The aircraft that you fly during your course will almost always be C152/PA28/BE76, regardless of which school you choose (or at least similar), so it doesn't matter too much what aircraft you fly. You need to look at how well you match up with the instructors at the potential school. If you get along, then by all means go for it. The decision to go charter or instructing can be made later during your training, however if you are going to be in it solely for the hours, and can't see yourself putting in all the extra (normally unpaid) hours to ensure your students get the training they deserve, then don't even bother, just go charter. Charter normally = faster progression onto twins, however a lot comes down to personality, and from what I hear most majors have about a 50/50 split between ex-instructors and ex-charter drivers, so either path can get you where you want to go eventually. Shop around, don't be mislead by sales pitches (money is fairly poor for your first few years as a pilot) and make the decision with your head. Also keep in mind that if you choose a school in melb, you then have to move there to train. Good Luck!
Arr