Since I was re-printing everything anyway due to the heat damage, I decided I would try to print all the parts at 0.3mm nozzle size.  Well actually, I consumed my last 0.4mm nozzle a while back so this was more a choice of attrition.. but anyway,  0.3mm nozzle it was.

Due to my previous haste, this required far more modifications than just changing the variable representing nozzle_dia in my code.  There were a lot more things dependant on nozzle_dia than I had accounted for, such as the ultimate thickness of the single wall print of the part_light_ring.  At 0.4mm this was still within the range of rendering a wall for Cura.  At 0.3mm, it was not.

A couple failed prints later I realized that 0.3mm at a 45 degree angle was too thin, so it was stopping the rendering half way up for the angled bits and renderings those areas just exceeding the threshold as a bunch of partial lines.  I was firmly in the area of mathematical rounding for determining if a single wall should exist or not.  

This of course, made a complete mess.  Doing partial lines for a single wall print just doesn't work.

I multiplied the wall thickness by 1.44 (45 degree angle horizontal thickness for a 1.0 vertical wall thickness) for those areas, and now have good code again.  

Looks like this worked.

Second to last part to re-print, and I'm back in business.