RE: Arrow fletching
Yes, too much helical will slow your arrow down, may cause clearance issues at your arrow rest, and potentially could "overstableize" your arrow. Overstableization happens with guns as well, If a gun has too much rifling the bullet will become "overstablized" and will not fly right. The projectile will point in a direction parelell to the barrel of the gun or the bow throughout its flight rather than pointing in the direction the projectile is traveling.