To the original RonC slider design I added a 1/8 x 1 inch box tube to the outside to provide a little more protection to the curved sill above. The same mounting holes were used, drilling a 1/4 inch hole on the inboard side of the box and a 1/2 inch hole on the outside of the box - to clear the bolt heads. An additional piece of 1/8 x 1/8 x 1 inch angle was placed aft of the rear jack point so support the box tube there. The front was just left floating forward of the front jack point.