Lo and behold, the solutions are out there:
- Keep pencil from erasing previous line when you start a new one.
The answer is buried pretty deep into this thread, so I'll reveal it here: Double-click on the pencil tool. Uncheck "Keep selected." Do the same for the brush tool.
- Make a brush that responds to tablet pressure.
After making these adjustments, I was able to create the following doodle:
This was all done with one brush. See how close the circles making up the necklace are? No way I could have done that before! But now I can draw a row of tiny circles, one right after the other, without hitting Cmd + D after each one.