I probably took a slightly different approach. If my homework was a handin task, then i'd do it, but for the majority of homework that i was given (which was just answering questions or whatnot and discussing in class the next lesson) i didn't do it and just made sure that i knew what we were doing.
Now imo i don't think anything more than 1-2 hours a night is necessary at this point in time. i'd even think that 1-2 hours every second night is ok at this point in time, however your assessments are the most important things, because whether you think you are ready or not, the first assessment is valuable in getting your rank up, because a portion of your grade will probably not have hit 'year 12 mode' yet and this is the opportunity for you to get in front early (take it from me - if you are in front early, you don't feel as pressured to improve your rank by the end of the year).
Now i experimented with a few study options throughout they year which included making notes every night and doing extra work to get ahead for what was happening the following lesson, but there was one thing that worked like a charm when it came to study: PRACTICE PAPERS for maths and sciences, and PRACTICE ESSAYS for english/humanities. Now because i did mainly english/humanities this year, i wrote a crapload of practice essays, including at the end of every topic i did a 'final essay' which was every bit of knowledge needed for that topic (addressing all dot points) to answer a question - and this will help you sooo much when you cram at the end of the year.
During the week i would do a total of maybe 6-8 hours over the 5 days of jotting down things that i didn't udnerstand and whatnot and making sure i understood them, and doing assessment tasks. and on the weekends, i always took saturday off (right up til the final exams) and i always worked hard on assessments on the sunday.
So ultimate advice, if you do subjects that require essays for the exam, start writing them now (you don't have to write all of it - whatever you're up to) because imo you learn so much more from practice essays that can be given feedback, then from reading notes, because you are applying knowledge rather than simply knowing it.
Good luck