This makes some sense and doesn’t seem rude.
I use Alibre/Geomagic which is very similar in many ways to Solidworks. Unfortunately, it won’t edit the stl files that you have supplied. I’d like to add nut traps in a few spots for the nuts I want to use but I understand why you don’t do that for a universal design. Openscad would allow that to be done as it is only math, equations and functions. It is arguably more universal than most other CAD systems.
Alibre does allow me to add nut traps to the generic.x_t tool_holder files, so if you could publish the parasolid files it would be almost as good. That was the only file I saw with .x_t files.