15x12s
I did a lot of digging to find this out myself, using off the shelf offset lca's, say using a 3" narrowed rear on each side, and a 325/50-15 tire and standard thickness brake rotors.
With 6.5" backspace the tire would sit around 1/4" from the control arm, 6" would have it sit Realy close to the qtr panel edge, and a 6.25" would be a happy median. You could also use spacers with different offsets to achieve the same as long as the math is the same.
The lca mounting points seem to be the biggest factor as mini tubs have around 16" depth. I might be wrong but if you use a anti roll bar, you might be able to use lca's that are completely offset all the way inward for more tire clearance, because the anti roll bar won't allow any twisting motion so the lca's would only have to travel up and down.

