I had a puncture in my smb recently. The outside material is nylon like fabric. After a few attempts, my repaire seems to work pretty well. Here is what I found work the best in my case.
1. Clean the surface real well. I used alcohol and mek.
2. I use aqua seal. The first coat, I used a lot of cotol. Basically I want very thin liquicd that can get soaked into the fabic. On my earlier attempt, I didnt use enough cotol. What happpened is although aqua seal sticks to material well, air still leak through what seemed to be laterally across the fabic. It seems aqua seal didnt penetrate the material enough.
3. Once above dry, about 1 hour. I add a few coat more aqua seal without cotol. This will take some time in between. What I found is with cotol, the aqual. seal become less soft less flexible when dry. The edge start to pill when I tried to give some stress test especially if the coat is thick. So no cotol after the very first thin coat seemed to work better.
I hopeothis help. Good luck on your repair.