I believe byuu, who developed the bsnes emulator, had a full CiB SNES set awhile back. He dumped all the games, scanned all the boxes and manuals, and the whole project took multiple long years of work. If you can find a link to his scans, you should easily be able to find the manual in good condition. You can also request it from theromdepot.com, they dump games and scans of manuals, boxes, inserts, posters, promotional items, ect. You can easily find a link to their Discord or subreddit. I'm not sure about this site's opinions on linking rom sites, so please remove my post if it violates any rules.
Hope this helped!