Thanks bojan.
The image below shows uStepper accepting STEP and DIR from a stepper controller.
https://drive.google.com/file/d/1HdA...w?usp=drivesdk
So planetary gearboxes have backlash. I'm still interested in whether it's feasible to directly connect the stepper shaft to the control shaft (1:1) would it be painfully slow, could increasing the supply voltage (increasing the stepper drivers ability to overcome the back EMF voltage generated by the motor, and hereby increasing the available torque at increasing velocities) speed up the stepper?
Does the TMC5130 look like a good driver?