72 Dart, mini tub, narrow rear, spring relocation

Hey guys, looking to mini tub, narrow the rear axle and relocate the springs for max clearance. Also looking to move the axle rearward an inch or so.

With the spring relocation kit that allows different mounting points, am I able to move the axle rearward an inch with no issues. Is it as simple as just mounting the leafs in a different hole and adjusting the rear mounting point?

Also, looking to run a 325/50/15 with a 15x10 wheel with 3.5" backspacing to give the wheel a deep look to it. I don't believe this would be an issue since I'm narrowing the rear end to the specific width right? I could run a 4.5bs but if I'm able to just narrow the rear even more for the 3.5bs, I would like to do that. I just don't want to run into problems with the tire hitting the spring.

Last question, The springs on the car are factory, I'd like to run a pretty stiff spring in the rear. My dads super bee is very stiff in the rear and I love the way it feels. I don't want the rear end to have much suspension travel in fear of any tire rub. Should I get some stiffer springs for the rear or just do the mods and see how it comes out. I can always get the springs later.

Any help is greatly appreciated, I have been screening the forums looking for the correct info but have not seen anybody that I can say "Hey thats the set up I want to run" close but always a different backspace or car or suspension set up. Thanks a mill!!!!!

PS. The fabricator doing the work is an absolute master his work is unreal but I don't want to go in his shop and not know exactly what I want.

I know this subject gets old but thought I'd just throw the direct ?'s out there.

-Paul