well since 99.95 is the highest, then ull have to be like top of all our courses. Its hard to say, since if theres a lot of smart people you might not need to be ranked as high, whereas if your're the only one who is capable of 99.95, then might need rank 1.
Same goes for 99, depending on how strong ur cohort is this fluctuates as well. just see how many b6 for past few cohorts and see what those students got relative to your rank, then chuck that into the uac atar compass thing.