Figure-1
Equation 1 and 2 plug in "AngleA" and "AngleB" into the equation. Calculate "PhaseErrorA" and "PhaseErrorB". Remember, if you are using Excel, you have to convert angles to radians since that is how excel or some calculators calculates. 180 degrees is 3.1415 radians.
Equation 3 find the difference of PhasEerrorA and PhaseErrorB. Take the absolute value. (Drop any negative signs)
Equation 4 gets you the answer that the rear pinion needs to be set at. Remember Excel will give answers in radians. Convert radians back to degrees if you are using Excel.