See now why do I post things like that? OF COURSE there's a cavalcade of irritating little things to clean up, each of them leading to a few hours of "huh, why does that happen then?"
Still, I am gradually tracking them down and fixing them. Latest fix was a bizarre thing of "when I shrink the heightfield to zero, why does it self-shadow all the time?" The answer was obvious in retrospect, and then the fix was easy, but oy oy oy...
But still haven't really started to write the "paper" as such.