When I'm spawn camping and The target is either not moving or moving slow enough to allow, I like to use the Zeiss sights to try and get a 1 shot 1 kill attack. I have a chart made up by BudGray in 2011, its still accurate. It shows the range based on Width, Length, and Height for the Pzr IV H, Panther, T34 (All), Tiger 1, M4 (All), King Tiger, M18 and the M8.
It is interesting to note that while the Zeiss German optics are based on 2/4 mils, the T34/85 optics are based on 4/8 mils, or at least in AH3, per Hitech.