First off, it's impossible to be able to estimate your study score from here, but it's safe enough to comment that you're heading in the right direction for a 35-40+. You're averaging 90% at the beginning of the year which is a really good sign. You should continue this way, then score an A+ on the exam and you'll secure yourself a 40 ss (providing that your cohort performs well on the exam).
One thing to point out though is, if these SACs are easy, you're probably going to want to be scoring 100%. This is really vital, as if these are really easy, then mediocre students may be able to score 90%, taking high ranks but are clueless in the exam. By separating yourself from these students, you're able to position yourself with the high achievers (95%+ zone) which provides you that security, as you know that your SAC scores won't be scaled down as much.
Good luck.