I messed around with different anti-backlash settings, but still couldn’t quite find any that worked well. [Anti-backlash takes up the slack in the gears whenever they have to change direction by quickly spinning them at the end of a movement.] I did also try moving the telescope in the same direction it was tracking after getting Andromeda aligned in the center and syncing on it in order to pick up the slack in the gears. It didn’t seem to help, though. I think this is a real issue, though, but only for the first few photos – when I’m taking the test photos after moving it, the first two or three are really bad, but then it settles, so I think that’s how long it takes to pick up the play in the gears at tracking speed, about a minute. Of some 217 photos I took, I accepted 102, and then DSS only accepted 62 of them. Also, they were all accidentally taken in JPEG. I went ahead and took darks and biases in JPEG too, but the dark subtraction doesn’t really work for compressed files, it needs to be pixel-by-pixel.
[Author's Note: Don't ever take astro images in JPEG format! You literally lose data. And then you can't stack them. (Well, technically you can, but it turns out awful.)]