Hi guys to add to the mix , if you use fb blades on a fbl head it will make heli respond faster to cyclic inputs , i tested blades on a 450 fbl heli ,the biggest change i found was if i used light weight fbl blades in a hover the heli was less stable ( 16g each blade ) i then fitted fbl bades at 28g each the heli was very stable and smooth to cyclic inputs ,i think this is due to the weight of the blades dampen down cyclic gains , if i adjusted the cyclic gains on the cyclic servos the heli would become more stable using light blades , if your new to flying run high weight blades turn down servo travel this will help you get used to the heli