I've never used the kits that are available now, but a few years ago, the ones that were out weren't worth a crap.
I had a '69 Corvette with a white ragtop which pinched in about the same way. I put a black fabric patch on the backside and carefully applied a dot of white silicone to the outside. I tried to give it some texture, but that wasn't easy.
When it was all said and done, I could barely notice it. It bugged me, but no one else ever mentioned it.
When the only tool in your toolbox is a hammer, you tend to see every problem as a nail.