I doubt you will notice a big difference at 20 unless you have a nice strong crosswind. Fob's were designed to guide big nasty broadheads. I have been shooting them for over a year and they do work. If you have any trouble with your set up just e-mail Paul the owner of Starrflight He will talk you through it. He has compiled a long list of tricks and tips with most of the drop aways on the market.