I let that project go. I'm just not technically ready for it yet. What I need to do is re-re-retrofit one of my mills with another pc based cnc (like my lathe project, using camsoftcorp). With their pc based cnc, I could easily grab the digitising data from a probe on my machine, because I could write the logic to do it.
There's nothing that beats a cnc controller interface that you can write logic for to suit yourself.