Canopy roller rails. Worked carefully on the proper placement of the rails. They measure 25 3/5 inches from the outer edge of each rail to the outer edge of the other, exactly, at both ends.
I drilled the roller rail holes to the proper size for a #8 screw and clecoed them in place. Made the cutout on both rails for the aft most screw which is mounted inside the canopy rail, and made a hole above those holes for screwdriver access.