So- going back to your initial pictures. The damage appears to be shy of each end/corner. When you clean that area up try and leave the original finish on the corners. I'd block sand to remove the dings if they're not too deep. Or fill with JB and sand. Then blend ( with 600 or finer grit ) in the bare aluminum to the black portion you left at the ends. I like to finish with a grey Scotch Brite pad- I use that same pad to dull shiny grips. Now tape off the sides, and the front and back straps, but leave the tape not fully adhered right up to the corners. Spray multiple light coats instead of heavy ones. I'll bet you can make it invisible. The key is keeping any color variation at the corner and make it a soft transition instead of a hard line.