All of this has been covered MANY times.
You have to move the front mount, or you'll move the axle BACKWARDS.
If you move the front mount to underneath the body mount instead of ahead of it, the axle will stay where it is.
You don't have to move the rear shackle hanger, it just helps the shackle angle.
If you use 56" springs instead of 52", all the mods to the front hanger are the same, and the extra length at the rear means no moving the shackle hanger.
Crossover steering is not just suggested with the 52" spring swap, it's a nessecity. Suspension travel is increased by so much that you will max out the angle on the push/pull draglink. You will also have no steering at all when crossed up.
Theres a thead in the garage with ALL of the big 52" threads in it. Do a search, it will help you. A lot.