I have 4x4 forged iron butt hinges, circa 1820. The leaf thickness is not constant. It is about 3/16 inch at the hinge pin side and about 1/8 inch at the outer edge. The slope is on the side with the countersunk holes. How do I make the mortises? If I make them flat to a depth of 1/8 inch then some of the hinge leaf will stick up above the door and jamb surfaces. Will the door close properly then, and must I allow extra distance between door and jamb for this?