So, the 7.5 inch chimney liner ovals from passing through the damper. I have an adapter to fit that to a 6 inch outlet on the top of the stove. How much will the band clamp on the top of the adapter pull in and round the ovaled chimney liner? I haven't tightened it up yet as the installation isn't quite complete. Is there something I can or should do to try to round the ovaling more? It looks like it will need a bit of sealant.