fitment help please

ok I've read the offset 101 thread but want know get a advice on my math.

Wheels in question 19x9.5 +11 hi disk and 19x11 +18 low disk on a Gs will they work?

I've had 19x9 +18 hi and 19x10.5 +30 normal on fine.

The 19x9.5 +11 will I've a backspacing of 129.75mm vs 130.5mm on the 19x9 +18 so only a difference of -.75 so I don't think that's a problem.

The 19x11 +18 low disk backspace is 155.5mm vs 161.25mm on the 19x10.5 +30 so that's  -4.75mm of backspace than normal disk. The problem I'd will it clear stock rear calipers?

on rears of a majority of vehicles you will be able to clear with slo offsets. whereas fronts its in the air and up to people who have tested with different brand rims and types.  if youre high disk, chances are youll clear.
and by the specs youve listed, there is barely any difference, remember, 24.5mm =1". 1mm is tiny.
Charley

any more help on this setup