Good try. Looks like you dipped a bolt. That’s a good idea. I hadn’t thought of that. I’ve often thought myself about trying to make a liner, kind of like you did. I think a better choice might be something with a Shore closer to the stock liner and something very stretchy. I think a good choice might be 30/30 Slide. They use it to make Masks. High stretch, a little stiffer in the Shore department, and highly tear resistant. I might order some and give it a shot myself.
I think where you went wrong is with the 10 Shore. Gotta be higher than that. I bet Ecoflex 30 would have worked better.