The weights talked about here really don't sound like enough to make a difference- The weight I see thrown out there the most is 12g, but it hasn't been made clear if this is a flat total static weight or the dynamic which should be oz/in or g/cm. 12g/cm is right about 1oz/in, and the back of the hand calculations show a tolerance of about .9oz/in for that engine (if someone can give me the actual crankshaft weight I can give a more exact number). If it's 12g/in, then that is well within tolerance.
This isn't a racing engine and doesn't see high enough rpms to require such careful balancing.