What kind of scope are you mounting? How big is the front lens (objective bell diameter)? For example a 3-9X 40mm scope would have a 46 mm objective bell diameter. You could probably use medium height rings. More compact scopes with smaller diameters would be ok with medium rings as well. However, if you have bigger diameter, I would suggest high or extra high rings. Yes you can use a Weaver style mount as they can fit on picatinny rails. As far as the sights go, they are both removable. For magnified scopes due to the eye relief, you will have to remove the rear sight but you can leave the front sight as it will not be in the focus field. It would be like it is not even there.