Operational Discussion

[Imp]

I actualy gave you the info so you could make a good guestimate if you disagree.
If look up thickness then add a bit for hardness (about 15-20% better than comparable British stuff for the time) you have your answer. As its only slightly off vertical could probably ignore slope calculation.
The hardest part of the info to find tends to be the Brinell rating (toughness) which might give it +1 on the armour rating if not factored in.