Well, this is a guesstimate, but assuming your internal marks are Band 6 worthy, then in Paper 1 - 36+/45, and Paper 2- 48+/60 should net you a band 6? Correct me if I'm completely wrong.
if you look at the raw marks database in the atar guidance/counsel not sure which one then it will show that is the past a band 6 has been a bit below 80/105