Your current working angles per your measurements are within .5-1 of each other. 0-.5 is ideal so you are close.
What you are describing with the pinion pointed down 3.5 is exactly what I just talked about. You are getting your working angles on both ends of the shafts as small as possible. It takes some trial and error. The problem with this strategy is that you may get an oscillating vibration. When the working angles are equal and opposite, you get a consistent hum or vibration, when they are not you will get a stronger vibration followed by none.
Equal and opposite and small working angles gives you the smoothest operation.
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Todd
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