This doodle just emerged from the heap:

It gives the envelope dimensions for the two PCBs in the quasi-extruded GPS interface case:

The overall idea was to subtract the envelopes from the interior of the solid case and print the shell:

Surprisingly, after minimal cleanout, the PCBs pretty much just slid into place and the setscrews locked them down.
Now I can throw out that scrap of paper…
The OpenSCAD source has the gory details; the actual dimensions don’t quite match the doodle, but that’s in the nature of fine tuning.