Hello: First time post. I am new to using a shotgun with adjustable sights. Situation: Rem 870P w/18" bbl Police Mag w/Wilson TRAK-LOCK Ghost Ring Rear and XS Post Front. I would like to zero the gun with 00 Buck @ 25 Yards and zero the gun with Rifled Foster Slugs @ 50 Yards.How do I do this? Thank you. Topspin :?: