Guys who are Mini-Tubbed please read...

I'm mini tubbing my 71 Demon and will be running a 10" rim and probably a 28" Mickey Thompson ET Street, or a Hoosier QTP in a 29". Both have section width of close to 13.5". My question is what backspacing to get that tire to tuck inside without rubbing the inside of fender or the frame rails. I have a Bill Reilly Street-Lynx triangulated 4 link coming with the shorter QA1 coilovers, so it will sit pretty low. So tire centering in the wheel well will be crucial. I would like to have tires/rims ready for Resto shop when rear is being installed, instead of installing 4 link then measuring and then ordering my rollers. Of course I will go that route if I can't find someone with concrete numbers.
I am running a stock A-body 8 3/4" with wilwood 12.19" Disks in the back. I think I will have body shop roll the inside lip of the fender for added clearance. I was measuring on a buddys duster tonght and it looks like from fender to frame rail is 14", lower rods with be attached to frame rail by the way. And I think with a 10" rim I should run 6.5" of backspacing to get it centered in the wheel well. Sound right to anyone running a similar setup? Any thoughts or ideas is appreciated. My suspension will arrive in a couple of weeks and my car heads for the body shop just before that, so trying to figure this out and get some rolling gear ordered as well.

Thanks Guys