The thread is the weakest link and the sun's heat and uv will rot out the threads, I just sewed the 36 inch window awning, the threads rotted and unwound on the arms, the big awning started ripping on the front side last year so it was replaced, white thread seems to rot faster than the black thread
Your repair might put a lot of strain on the small areas of the screws, if you can sew the fabric it will spread the tension of the fabric on the channel rather than concentrating the pull force on only small areas, this can rip the fabric.
navegator