Well I can say this, a lighter flywheel is never a bad thing, and yes, there are lighter ones on the market in 2-4shoe configurations. A lighter flywheel will allow the engine to spool up quicker as it has a lower rotating mass and generally have vent holes to help keep the clutch shoes cooler, this helps to, to lower their weight. Good luck in your venture, GPM and Robinson Racing are some carriers of lightweight flywheels, I have used them in the past with good results. As far as size goes, it really depends on if you are going to use a bump start or not, if so, don't go with a smaller one unless you know for sure that your starter will still be able to make contact.