I really don't know where to begin. I appreciate your having looked at the file MusicBoxMV39, but you (understandably) drew the wrong conclusion about my use of the -3000cm Gravity setting. Notice the file is number 39 in the process. In my cave that means there are 38 files that came before, starting with a whole slew of ones (that I didn't post) that used default settings that didn't get the job done. You know, after awhile of nothing working as one would expect, one starts to try unusual and unexpected values and settings out of simple desperation that something, anything, will work. That's just how it goes, but I can understand your puzzlement on seeing that 3000 value and not knowing how or why it came to that. Anyhow, the fact that, besides desperately trying a gravity setting three times the default, the fact that another one of those vain attempts to improve things, increasing sub sampling, was actually a trap that makes the whole simulation fail in the most absurd and confounding way imaginable, in this case making it look like gravity strength is changing over time or distance from start. (Silly me for not reading the manual better! 😄)
The upshot is somewhere around MusicBoxMV43 I finally gave up on Simulation altogether just to make sure I hadn't lost my mind and went back to Bullet Engine where, shazam!, everything just worked as expected, with all the settings actually doing what their name suggest instead of literally none of them doing that.