I bought a few rtic soft coolers last year - I love them, but all of these soft coolers have hard to use zippers. The new ones come with nice nice handles on the zippers so I printed my own... it seems to work and I attached it with a zip tie, hopefully the pictures make the path for the zip tie clear. I've put one on my two rtics and yeti and so far so good! If you have big hands you could scale it up...
Pretty straight forward. It needs support though...