So I finally got my extruder polulululu installed. I measured VREF as installed on the X/Y/Z axes, and saw 0.7V, 0.7V, and 0.45V — I’m assuming the 0.7V (=>1.4A) is because we want to (nearly?) double the current for the pair of steppers.
I set my extruder to 0.45V (0.9A), but I have no idea what the current spec is for the “import extruder” stepper. Recommendations welcome.