This conversation is discussing angles in the vertical plane. What about the offset we create in the horizontal plane when we center the pumpkin, which offsets the pinion a bunch? Also, doesn't the triangulated 4-link cause the pinion to drop down at the u-joint end during the majority of the travel in both compression and rebound? I don't think we can set these angles where we can expect no vibration. Just hope for something that we can tolerate. And driveline vibration can drive a guy nuts trying to correct! So many variables to deal with from engine balance, torque converter, etc. right on back. If Roger can modify tunnel for later adjustments, that would help in case he does have a vibration to deal with.