Ok so disclaimer I don't do further/general but I have some friends who do the 1/2 and the 3/4 in year 11 so based on what I heard from them and teachers:
If u A) Accelerated methods and B) Get 80's...you will slay. Seriously, the top end of further gets really competitive because so many kids like urself do further and can just...blitz it, so like losing 1mark is equal to a whole SS point. However, my school, which is exceedingly average in vce, like median SS of 29-31 every year, over the last 4 years, 16-26 kids have gotten 40 or above SS every freackin year, one year 26 kids got above 40 for further math. They only get like 3 for methods and 0-1 for spec (this is raw).
Don't underestimate it, it does require work contrary to what some people may say, but with ur sores, the math part you will be great at and pick up easily even without the 1/2. Just make sure to go over osme key concepts over the summer holidays, double check urself on mistakes and really be carful.