I will be doing spring relocation and mini tubs in the Duster which has a 7 1/4 rear in it. I have an 8 3/4 housing that I will size to fit whatever calculation I come up with - which I haven't.

I'm wondering if I should pick my wheels first then calculate backwards to arrive at the proper housing length.

wheel width + 2" for tire bulge - backspacing = housing length ??