Sounds good. I just ordered some 5x100 56mm CB 5mm ebay alum spacers and will mill them down to what I need. I went to mcmaster and a a 12"x24" sheet of 0.062 6061 was more than these spacers .
I just checked my car with 225 star specs and the only place I see that could rub inboard is the tire on the plastic liner that covers the chassis right where the shock mount hits the body. As my car sits, there is 7/8"-1" of space, however, given our rear suspension gains camber on compression, and the fact that there will be 10mm more rubber there with the 245s, I can see a risk of rubbing there.
Did you only rub on compression?