driveshaft angles

I used the Tremec app on my phone, hoping they know what they are doing.
You do need to be careful (as I'm sure that most on here could figure out) not to have your phones buttons affecting your readings.
https://www.tremec.com/menu/tremec-toolbox-app/

I used that too and found it very important to make sure to keep the phone facing the same direction for each measurement. If your screen if facing the drivers door when measuring the engine, then it should be facing the drivers door when checking the rear. I initially just ran around the car and got measurements that were way off... but it had the angles swapped on the rear end with regard to the engine.