Compensation for the video camera's axis alignment is something the software ought to do to make it easier. You should be able to set the cross hairs on a feature. Raise or lower the Z a determined amount, rezero the cross hairs by jogging, press a button, and be done. The geometry is pretty darned simple and would be easily compensated by the software.
I'm supposed to be a beta tester for Tormach's upcoming video prober. It has some real special software with it, and that software will also be available separately as I understand it. I don't know if it will do the alignment compensation or not, but I'll be on the lookout and I'll write about the whole thing on
www.cnccookbook.com when the beta test is done and they've made all their improvements.
I'm really looking forward to it.
Best,
BW