wagon quarter glass rubber seal
Once the glass is installed, no need for "flexibility" as everything should be solid and in place. The gel-type does seem to work better on rubber items. Don't get too overly ambitious with the sanding of the mating surfaces....you do want a little "roughness" to it for the gel to work it's way into the nooks and crannies.
Our customers have had no issues once the glass is installed.....but I might mention that we do recommend professional installation if this is something you've never done before. We have sold quite a few of these gasket sets in the past, again....no major issues for fit and function.