"A flywheel will be the most effective flywheel if all of the mass is concentrated at the farthest distance possible from the axis of rotation."

This is what made me think that you meant that the center/face of the flywheel needed to be shaved,,,

But alas, this is a clutch thread, not a 'flywheel lightening theory' thread and I don't wanna thread jack,,,,, I do enjoy learning though! Is there already a flywheel thread or what?