I was doing more graphics experimenting, including in the XML file, to squeeze more out of Elite. Ended up finding that setting directional shadow quality to Low seems to fix the flicker. It's not perfect, in fact it almost seems to remove directional shadows all together, but at least no more seizure strobing! 
Source: https://youtu.be/rlyclTyFzmo?si=lIVfBVJVhK8ZY53-