There is another thread with this subject, do a search for "headliner" and you'll find it. Here is my experience: Another member did this job and made it sound do-able for me but in reality, I had to hire the job out. Partly my fault, I'll get to that in a bit. I bought the material and while it was on the way, with hope and optimism, I pulled down the old headliner in my MS400. I took the old stuff home and, using the old pieces as a pattern, I cut out the shapes for the new headliner.
I headed for the boat with my rounded off putty knives, soapy water, step ladder, and my new material. My enthusiasm soon became "why did I do this" when I could not push the material into the center channels no matter what I did. I managed to get it into the side (perimeter) channels but I just kept messing up the edge in the center and basically making it even harder to stuff up into the channel.
So, I hired a guy who had done Whisper Wall before and had the official tools. The first thing he said is that I shouldn't have cut out the pieces, he would rather work with the full 54" wide piece because that makes it easier to push it up into the center slot. Also, he had the official tool for Whisper Wall which put my putty knives to shame. It looked like the blade of a scythe with a smooth radius, not just a square bladed putty knife with rounded edges.
He ended up taking about 6 hours to do the job, but he told me it would have been half that if I hadn't cut the pieces out. The right tool also made a difference.
Another thing I noticed was it is important to start in the middle and work toward the ends, not go from one end to the other, which I what I tried. When you do that the material stretches too much. Better to push in midway between fore and aft to start and work toward the ends.
I hope you have better luck than I did.
https://www.fabricmate.com/shop/pro...gonomic-fabric-finishing-rocker-tool-new-3114
This is the tool, I recommend getting it.
