So if the 5/7 students perform pretty good,is there a good chance I wıll get my sac scores scaled to a C+ or even a B. Im expecting a SS of around 28 with 50% average across all 3 GAs
I'd say it's more than likely under those circumstances that you could get anywhere from 28-30 as a study score

I guess you'll find out 5 days whether my prediction is right haha, I hope you get on the higher end of that range

Just out of interest, what if you and another person have the same sac scores? Obviously you can't have the same rank (as I've heard from vcaa), so what would happen then? Particularly a problem for rank 1.
Whilst I have heard that it can be problematic to group students together at the top with the same SAC score, there is no actual rule against it. The students with the same SAC rank tend to receive an approximate average of the scores that make the top. Say for example both of the top two students in a class got 95/100 for their SACs. On the exam however, student 1 receives a 90% and Student 2 receives an 85%. What VTAC does in this instance is calculate an average of the two scores, giving an effective 87.5% for their exam contribution to their SACs.
Normally I'm sure this kind of instance is where they would likely call upon things such as the GAT, Indicative Grades and seeing if these students can be classed as outliers. But I believe in the case where these on't separate the student, I believe VCAA averages the top scores, disadvantaging one student slightly over another.