Just to make sure I am understanding this correctly, you are saying if I bind a key to Throttle – Remove Trim it will set SCM speed to 0?
Set Trim and Remove trim work together. If push your throttle forward 50%, set the trim and let go of the throttle your ship will fly forward with 50% (the sticky value is remembered). All throttle inputs are now done from that trim position. If you press release trim, that remembered value is reset to 0.