Setting pinion angle

I think I would get an angle finder, pretty inexpensive at Lowe's, Home Depot etc, and see where it's at now with the rear in the truck.

Then you would need to remove the perches and get 2 new ones, set the rear in the perches on top of the springs and find the same angle and mark it.

The only thing I'm not 100% sure about is whether the move to the top of the springs would require a bit of a different angle. Hopefully someone can chime in with their 2 cents.