Pinion Angle? Do I have this right before I cut it up?

The previous owner installed SS springs on my '67 barracuda. I just rebuilt the 8 3/4 and decided to check the pinion angle as it didn't look right. I haven't driven it down the road more then a 1/4 mile as I've been busy doing other repairs. So I don't know if it has any vibration at speed. Here are the measurements taken with a harbor freight angle gauge. The vehicle is on it's wheels and is primarily a drag car.

Measuring off of the output shaft of the trans, I have 2 degree downward angle from ground parallel (negative 2*). The yoke on the rear differential has an upward angle of 4 degrees from parallel to the ground (positive 4*).

If I understand this all correctly, while under load, my pinion angle should be parallel to my trans angle. So if my trans angle is -2*, my pinion angle should be +2* under load. Which would mean when set correctly aiming for a 5* downward static (they say 5* to 7*), I should have a static pinion angle of -3*???

With a current setup of +4*, it's clear I will have to cut the perches off and reweld them correct? As I'm told shims past 4* aren't safe, let alone the 7* I would have to move it.

So before I cut it all up tomorrow, tell me if I'm understanding this right?

Thanks a ton!

MM