I never bothered to make a table; I just do the math mentally.
Here's what I do for the T34-85:
The sight has little caret marks "^" separated by colons ":". If your target is a Panzer and it is broadside and takes up the distance between two ^, ie ^ : ^ then it is at a range of 800 yds. So the math is easy. If it is further away and spans only ^ to : then it's 1600 yds. If it spans ^ past then next : but only half way further to the following ^, then its 1200 yds. If it spans ^ : ^ : ^ then it's 400 yds (although I tend not to set the range to less than about 600 because there is a parallax error between the sight and the gun barrel). If the Panzer is head-on then just half all these ranges (since the Panzer is about 1/2 as wide as it is long). If the target is a Panther, which is a bit longer than a Panzer, then add a bit of range to what's listed above.
Now how much to lead? If the Panzer is traveling across your view lead him by two ^, ie ^ : ^ : ^. If the target is a faster tank, say a T34, then lead a bit more. If the vehicle is much faster, like an M3, lead almost the entire set of ^. This presupposes the vehicles are moving at maximum speed; you can judge that visually and make corrections.