By the way, I have noticed a couple other small flaws with the shadows. Any shadow cast on to the shadow of the thermal solar panels will overlap and turn that area even darker, for example in the lower left corner in a field with panels. The panels will cast shadows on various "flat" and "low" objects but not on other objects. Even weirder, objects like solar panels and heat pipes only receive a shadow with certain placements relative to them (like, what). I have uploaded a screenshot on GitHub along with the zip.
I am not a programmer, but these seem to be side effects of not being able to use separate shadow images for the heat-pipe prototype. I guess these issues are either not extremely noticeable or not likely to be encountered in most use cases, and I like the improvement overall, but still...
I can't really think of any good solution right now (although I am looking into finding one). Sorry for the trouble.