As for cutting the gears, ...what I did and found to work really well was to use some 1000 grit sand paper and lightly sand off the hard edges. I did this to all the plastic gearing. Just do it a little, to take off the hard edge on each tooth. After, clean w/ soap and water, let dry then lightly coat w/ a very fine spray of silicone. -use very sparingly.
Others may have other suggestions..