I was going to cut it lengthwise below the radius of the upper corner then make about a 9 or 10° cut below it removing a triangle piece from each side. Then the top would slant down 10°. I know the rear end of the side walls would have to be tilted inwards more to meet up with the roof. However I thought further on the project and realized that if my roof stays the same length and I simply tilt it down then it won't extend to the back of the bed. It will become the long side of the triangle. I might scrap the idea and maybe use the frame to build something maybe using new aluminum sheet for a cover. The aluminum on the cap is that textured crap they use on trailer siding so it's not very smooth.
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