After some observation, investigation, and experimentation, I learned something about those lights that makes them even nicer and explains a cryptic notation in the instructions.
I knew that the touch ring controlled the blue night light, and dimming the the reading light. The instructions say:
Tips: Lamp memories your desired brightness and it stay on last time brightness level when you turn on next time.Dimming range 15%-100%.
I never could get that figured out, because of the way the touch control works. Then, when I was rewiring the lights from my temporary 12 v connection to the new under-dash fuse panel I installed, I noticed that a light that's ON when power is removed retains that setting when power is restored.
So, I have now added a temporary dash switch that controls all 4 lights. Much more convenient than having to stand up and touch the lights one by one. There's a hole in the dash for a matching Carling switch that I'll use as soon as the ones I ordered get here.