65 barracuda need help with rim backspacing

I already bought the spring relocating kit so I will use them, but also it will let me move the axle back slightly to better center the wheel front to back. I didn't know that you could also accomplish this with the offset hangers. I thought about using spring sliders on the rear as well.

the slider are pretty trick. i have mine just tack welded in case i have to add spacers to raise the rear of the car once i get all the weight on the rear.

cuda rr slider.JPG