Question of leaf spring angle and rear leaf shackles

I wouldn't change anything until he gets all the weight, including weight box, gas tank, fuel, etc, etc, loaded onto the rear springs. Otherwise he might have to undo what he does to the front hangers.
He doesn't have to actually install everything but simply weigh everything that will be installed and put that much weight over the springs. That's what I do when I install a Mustang II front end on a frame. I get the weight of everything on the front end and use weights to load the front to get an idea of what the ride height will be before I finish welding all the front end suspension parts in place.
Treblig