I beams can get bent, Shawn. A good competent alignment shop that can do big trucks will have the equipment and knowledge to tweak those I-beams and get the caster and camber right.

As with any frame work, when you Z a frame, you have got to support everything so that it wil not move when you start repositioning things. I'm sure you've heard the old "measure twice cut once"? Don't believe it. Measure, plot, and plan at least 3 times BEFORE you cut anything!!!!!