what is the best way to sight in my crossbow.i have a horton hd175 and shooting mechanical broadheads.i currently have it sighted in but during the rush to do so (bow season was already underway) i have the dial set on 4or 5 and am able to hit the traget well.i would like to go back to zero or matbe one.if anyone has a prefrerred method that works well i'm all ears.thanks.