RE: Fast Flight?
Art, have you tried 450+? It has a softer feel to it than even dacron. Dacron might be easier on the bow, but I doubt there's much if any difference vs. shooting an arrow that's a few grains heavier or lighter.
With mebeing the type that can tear up an anvil with a cotton ball, after about 10 years of using them I'd have shattered a bow by now if it made that much difference.
Chad