Pinion angle question

So I need to mock up my ubolts bolt everything together and lower it down check it again. Ok thanks I'm gonna have to get my tires on my rims then lol
Another question my leaf springs move side to side about a 1/2 inch or so is it ok to push them over as far to the center as I can to help with tire clearance or will that cause wear on the bushings and springs?

Support it with blocks under the springs where the stud is that holds the spring pack together.
Then move the diff and perches it to where you want it and tack the perches on.
That's what I did and it worked fine.

As far as the car being level, just go off your trans pan rail or output shaft housing end and subtract your preferred pinion angle off of that.

You could turn the car on it's side and still know where the perches go for angle.:D