I had the hardest time with linings, I ended up installing and removing two or three times until I got it right. I gave up on reverse kerfed and went to standard and installed in about 4" long sections and that worked great. I used a bunch of those cheap little black plastic spring clamps with the orange on the tips.
My problem was I'm doing an O-size shape and the waist is pretty tight. At that point, you have to bend the linings the shape of the sides (which is easy because of the kerfs), but you also have to bend it to conform to your back/top radius and the waist is a high point in that regard. That made the lining want to flare out towards the interior of the waist, so I kept getting gaps. That may or may not be the issue with yours, just thought I'd throw that out there.
