FWIW, this kit only moves the springs 1/2". MP advertised 3/4" but that's impossible because there's only 1/2" of clearance between the original hanger and the frame rail, so there's only room for 1/2" movement. Still a good kit and good way to gain some clearance for bigger tires.
I somewhat respectfully disagree with your statement. 1st the perches were 41 1/2 center to center, 2nd i just measured the rear shackle offset and its 3/4", maybe the springs go outward on a angle i have no idea but will check.