I am blow away at just how accurate GE is once transformed to a known surveyed point.
I really expected the elevation to be off by feet, not by tenths.
The horizontal is spot on. I really was lucky in picking the right point on GE.
I am also calculating everything in grid coordinates to keep each point in the same datum.
I will test other locations to see if the residuals are uniform. My best guess at this point is that each location will vary slightly.
Would I use GE for Lat/Long for GIS mapping, yes I would. It is accurate enough for that type of mapping. You do have to have a good known point to adjust to.