Desertdogg the easiest place to measure your engines angle is on the front pulley. Lay a straight piece of wood on the surface, top and bottom, and put your digital angle finder on the wood. Subtract 90 degrees from whatever angle you find and ideally it should equal 3 degrees down.
At the rearend, with the driveshaft off, move the truck so the yoke is up and down. Use the same method with the little piece of wood across the yoke and your angle finder on the wood. Again subtract 90 and it should ideally equal 3 degrees up.
You want weight on the suspension and truck sitting on a level surface. You can put blocks under the wheels like you said as long as they are all the same height.
The best way to think about pinion angles (with one piece driveshafts) is to imagine a straight line going from the center of the front pulley bolt and out the centre of the trans output shaft and continuing to the back of the truck.
Now imagine a line coming straight out the rearend forward. Those two lines should run parralell.
Here:
https://www.therangerstation.com/tec...onangles.shtml
Just for reference I was playing around with my engine angle. I shimmed up my trans crossmember 3/8" and it decreased my angle about .7 degrees.