It was kinda ghetto, but what I did was take a know bore and probe to center it. Then manually jogged over and read how much it moved in each direction.
I entered the probe offsets x-/x+ etc, such that it when I reprobed it manually jogging would yield equal results in all directions. I think it's within 2 thou or so on my setup. For me its more about getting the corners and center of the bore, since we cant really do in program measurements without macros. But setting XYZ offsets and tool offsets is awesome. Oh yeah, I added tool length offset measurement too.