Tincup's 63 Dart w/5.7 Hemi

Sorry tin, I need to borrow your mind once again.

I'm going to be ordering suspension from bill tomorrow hopefully and I need some help with some rear axles dimensions. I will be going with the fabricated 8.75 rear end from moser with 33 spline axles and the ford 9" housing ends. I'm going to be doing the magnumforce relocation kit like you did and I was wondering what your spring perch location was? Do mopar leafs curve out at the back or anything? I didn't know if the frame rails stayed straight thereafter making the leaf spring straight as well. I just need to verify my measurement.. Also, as my wheel's backspacing is different from yours and I "think" my tires are a tad bit wider, can you just give me a nod or shake on whether or not my axle to axle outer measurement sounds right? I'll list the wheel specs as well!

Wheel specs: 17x10.5, backspacing 6.8", offset 28mm(1.10")

Tires(just for kicks): 315/35/R17

Rear end measurements:

Axle to axle(outside): 54.75"
Axle offset will be 2.36" so that would make my housing dimension 54.03"?
Perches(center to center): 36"

Sorry! I'm a younger guy and this is my first time doing this to be honest..
Thanks again as usual, you are a great asset!
Ryan