Hey, so I'm not a current HSC student (I graduated last year), but I can definitely help you out, as someone myself who also struggled with creating a suitable and efficient study plan.
So with your HSC exams about 2 months away (English first), until about the beginning of October or one week into October, I would spend an equal amount of time on each subject. Obviously, you can tweak it a bit and so depending on what your weakest subjects are, you can spend more time focusing on those. 2 months is a lot of time and I can believe you can go over the entire syllabus for your subjects quite a number of times over, putting you in a very strong position for HSC exams. Once that first week of October is done, you can then spend the next 10 days or however long it is solely focusing on English, so Paper 1 and Paper 2. This is what I did but you can obviously play around with it and see what type of plan suits you.
Also remember that more doesn't equal better. 5 hours of dedicated and efficient study will always be better than 10 hours of inefficient and laid-back 'study'. Doing every subject each day probably wouldn't be the best as well, just because of the sheer volume there would be to retain. Working on one to two subjects a day would be far better and still would give you enough time to go over the syllabus thoroughly. Once you have done this, you can get straight into past papers and questions, in my opinion, the best way to prepare for your HSC exams.
Pretty much, the hours you study a day will vary from person to person, so try to find the right amount of time you can spend studying a day, whether it be 5 or 12, where it is all dedicated and efficient towards your end goal. Good luck for your HSC exams