DO NOT, I repeat do not drill holes in the prop blades. If your engine is running at full throttle at say 12000 rpm and the prop blade breaks, it could seriously hurt you or a bystander. The centripetal force on a spinning prop is insane and the prop blades should never be altered. Rather use the nail polish idea or sand some off the back of the heavier blade but don't change the shape of the prop( aerodynamics). Good luck