After making it part way through the dreaded calibration procedure for a delta 3D printer, it does not seem that bad. I tried to write a quick overview that may be helpful to some.
I am not done yet, but I am within +-1mm of flat. I hope that the autocalibration procedure will take care of the rest. I think that the residual error is from loose tolerance on my mechanical build. The solution would be to check the squareness of the frame, and re-print the diagonal bar carriages to be exactly the same. Mine were printed at different times with minor design changes, and don’t perfectly match.
Centering the extruder tip on the print bed is a matter of position of the endstop switches. This is very hard to correct with sub-mm accuracy. I may add a fine-adjustment screw to the carriages for these small adjustments.