Hi I have updated from Canon 40D to Canon 7D. I am not too good in my maths and have tested several settings and will like to compare my setting with yours hopefully. I am using the NN5 with rotator n16 without battery grip.
Canon 17-40mm
17mm setting A=58 B=96mm still not perfect but very close what do you think
29mm setting A=58 B=? Still trying to find best setting
40mm setting A=58 B=95mm still not perfect

I wonder if someone want to reveal is setting with using the 70-200mm

Thank you