It's interesting you want to do science - you seem like more of a humanites/letters kind of person. It's good to see you have a clear idea on what you want to do though.
I think you should be set ATAR wise, I must say. I didnt say this in your thread, but I fiddled with an ATAR calculator when doing your estimate and it said 99 exactly, so if I had to pick an exact number I would say 99.00 (I am confident with this estimate, which is unusual for me). I also gather you want maths to count towards your ATAR a lot (I was the same, maths took so much effort for me).