Fiddling some more, because what else is there to do on Christmas Eve while waiting for the food to be ready (don't worry, I'm doing my part of the food prep)?
The suspected bed gap is not an issue, I literally can't get a piece of paper under the nozzle when it's at minimum height, but I can still move the bed by motor.
I trying running the X motor back and forth somewhat, and while it rumbled somewhat, it didn't grow warm at all. After marking the initial settings, I adjusted the pot a bit up and down, listening for skips, but it rumbles just as much when at a higher setting as when at a lower. Since it seems to have had problems with the filament getting slightly stuck, I'll increase power by 1/4 turn. Didn't help much, still getting random skews, now in both directions.
Trying with layer height 0.3 and width 0.55. I don't quite get why the width is a constant ratio of the height. I should think, once the height is less than the nozzle diameter, the extra material would squeeze out to the side. But I guess the interface is smart enough to adjust the feed rate accordingly, that might just put extra strain on the output. Not sure.
With 0.3 layer height, it was clear that the nozzle didn't get close to the bed initially, and the first layer only stuck a little bit, so any kind of sticking to the head made it start to clump up again and eventually gather the whole thing up, like a Katamari Damacy. Grumpf.