And it's still morning!
When I haven't been crashing, I've been noticing that the intersections of my horizontal 8's are even more deformed than my loops, and tried to work on it. This morning I was flying air patterns while breakfast was cooking, and I noticed that my hand traces just about the exact weird not-quite circles that my horizontal eights do. It seems that I'm coming up against the limitations of my creaking, popping, binding shoulder joint, and that's being reflected in my flight path.
So: I got something to work on -- maybe loosening up that shoulder will help my eights!