Currently only one RPM signal can be connected.
Is it possible that there is a typo in the formula for
Extruder_force_at_rated_current = Motor_holding_torque * Extruder_steps_per_mm * 0.007
for 0.9deg/step motors? I assume the multiplier at the end is missing another zero.
When I calculate this for a motor with equal holding torque once for 1.8deg/step and once for 0.9deg/step I get an order of magnitude more force for the 0.9deg/step motor. That seams unlikely.