Well, I'm annoyed and grateful. Spurred on by your suggestion, I got a metric tape measure. Well, I found out that my working area is only about 780mm in Y with the router spindle. I also found out that my settings gave me 702 mm for what should be 700 at 197.000 set in GRBL. So, I adjusted to 197.500 and that does seem to be accurate to the mm now.
