> There are already some Imperial sizes included in the script.

Ah... Thanks!

> What exact settings would you use in the rebuild process?


I think it would have to be relative to the thread size, but when I did a Rebuild on the profile, using [0.0005 mm] in "refit" mode (for the M3x0.5) it seemed to produce a reasonable facsimile.
Though not perfect, it may be worth trying out.

A place I often use Rebuild are on curves that would later be extruded and then filleted, as Fillet will make separate surfaces for each split in a compound curve.