This weekend I was able to assemble the x and y axis. There are now only a handful of smaller parts missing (motor & router mounts, leadscrew nuts etc.) I will order the leadscrews next week. About 7 hours total this time.
A second plate was glued over this one to add stiffness. This does trap the bolts to the pockets and the blocks can't be taken off without tearing them apart.
Using a dial gauge to measure the flatness & straightness of the table surface in reference to the axis plane.
The dial gauge has resolution of 10 micrometers and one millimeter makes the needle turn a full rotation. The table has less than 1mm variation and by some adjustements I can probably decrease that to less than half a millimeter.