There is a thread that contains all the information you need with respect to brakes and wheels and spindle heights. I'll bet Bill verburg was on that thread if you want to search the subject and his name.
The max with 15's is 19mm using Fuchs, so if you're never going to use less than 16's, add a half inch. IIRC, that comes close to 1 1/4" for the 16's.
Here's some reading for you:
Raised Spindles VS. Big Reds = collision?
raising spindle height on struts
Raised spindles with 15 inch wheels?