Finally had occasion to calibrate the machine (the second cut was intentionally done with a decalibrated machine) and it fits together quite easily — probably one could use a few fewer tabs in the .c2d file.
A further improvement might be to try cutting the areas for the finger joints only 1/2–2/3rds the thickness of the board deep, and shortening the fingerjoints by the inverse of that amount — that would hide the joinery, and slightly increase the gluing area.