Go with the HSC marker they tend to be more objective in their marking whereas everyday school teachers have their take on a text and if you disagree with them, you may get penalized.
Lol, analogy wise, first assessments are warm ups to a sporting match, half yearlies are about 1st quarter, then yearlies are half time and the last few minutes are the HSC :)
Just remember guys this is your last real holidays so make sure to get some much needed R & R before the long road ahead next year. If anything I would suggest reading your English texts, start reading ahead in some of your textbooks and get ahead (even just a chapter or 2) in maths.
In terms of content they might be of some use but in terms of the HSC I doubt senior lecturers/PHDs can understand what kind of simplicity is required for the HSC..
Teachers may decide to simply stop reading after the 800 word limit, in which case they might miss out on critical closing statements, conclusion etc...
Most short answer are worth more than 1 mark, so you will get partial marks if you are partially right, i.e. have pointed out some techniques, analysis and quoted something from the text.
You're risking it with 10 units if you bomb out in one of your tests and 14 is a bit too many. So I would recommend 11-13, that was you have some sort of insurance in case something doesn't go your way.