So, it appears that the Thingiverse Customizer is currently broken, so progress on making a Customizer-friendly version of my OpenSCAD file is kind of at a standstill.

Opening ANY file in Customizer seems to generate the following error:

Note: This particular error is from a "Featured Customizer" Thing - I thought maybe is was my code, but it is affecting every Customizer thing I've tried over the last few days.  Not my code, not my site, no apparent feedback channel or timeline for getting it fixed.  I guess I need to just lay it aside for a day or so and read some documentation instead.  *Grrrrrr*