nikhil vasan did 16 units and managed to get 99.95 and state ranking in phys and maths i think
so do what u r capable of, i know many people who do extra units just to increase their knowledge and acquire more skills from different subjects and not limit their knowledge to one field. Ultimately...
Yes, you're right, but I'll take a break for a week after trials doing extra curricular stuff, and going to the gym, should be a nice break from studying.
Then I'll get back to doing past papers all day =)
Since trials are over, I'll spend my time doing extra curricular stuff, they are so much fun =)
and I used this http://mathim.com/Mathstuff a guy taught me how to do do contour integration there ^_^