I bought a new Patriot Victory cover for my 2008 supercrew f-150 4x4 with the 5.5 ft bed, the cover came with 6 clamps, 4 large ones and 2 small ones. I used the 4 large one in each corner. the paper instructions don't show where the 2 small clamps go, the instructional video don't show where the 2 small ones go. I tried to place the 2 small clamps in the center, half way between the 2 large ones. but they didn't fit right. could anyone tell me where the 2 small clamps go?