Even if you do high scailing subjects you have to be good at them
if your ranking is like bottom 5 on subjects lik eco,chem etc
no point
i wouldn't choose subjects just because they scale you up
You should select subjects that are of genuine interest to you. And they should be relevant to the courses you intend to go for in the uni.
Do not use good scaling subjects to get into a high UAI course.
Like I have 4 unit maths becoz I love it.
I have Phsyics becoz I love it. I'll continue these in the university.
If I had to become a doctor then I should be into Biology etc. Not use other subjects to get into Medicine or Law.