I'm working on a traverse mechanism that only requires to lift and lower a pitot tube (very lightweight) for an experiment. Speed is of no importance, I only want precision and accuracy. It's an inexpensive project, so I was considering using a motor and belt pulley system to move up and down. The distance is at most 12 inches. My question is, is it better to use a stepper or a servo? The only advantage I'm seeing for the servo is that it doesn't require calibration for its zero, but its more expensive. Which one do you think is best for the application?