Mini tubbing, springs and backspacing

A much discussed topic yet I couldn't find the answer to my problem.

I've got 8.5J wheels mounted with 255/60/15's , they are too wide on the outside and will require me to alter the outside of my rear quarters. The offset/backspacing is aprox 3.5"

This means there is about 1" between the rubber and the rear leaf spring, so I could fit this wheel/tire combo with a different wheel with a different backspacing.

If I were to mini-tub where do I put my leaf springs? I can't see the point without relocating them.

What's the ideal backspacing and how close can I put the tire to the leaf spring safely so it doesn't rub with travel etc.?

TIA
David
Author: admin