I think you are correct for P&G driving. This article explains it better than I could:
Flywheel lightening & performance gains from lighter flywheels
I'll probably look into getting a stock VX flywheel or whatever I can find cheapest. I don't see any harm in trying a VX flywheel. I doubt I'll go any lighter due to the cost of aftermarket, and I haven't seen any results indicating I could benefit with my driving style (steady speed highway).