I made a post about this before, but can't find it. Remember a few points as to why worrying about scaling is silly:
1. Chosing subjects based on scaling is not a good idea. Rather, you should chose entirely for whether you like, and (for the purposes of marks) will do well in. If you chose a subject that 'scales well', without considering the content, you may dislike it. Subsequently, you would do poorly anyway.
2. If your school performs quite well within your candidature, and you perform quite relative to both your school's HSC performance and internally, scaling has marginal influence at higher levels. This is especially so considering any 2U mark will only make up 1/5 of your UAI.
3. You can't do anything about it.
The best thing to do is to just try your best and encourage your year group to study hard.