[thirt4]

Thanks for the replies. What I have encountered is that this gasket is too wide. The outside edges are approximately 1 inch beyond the R/L edge of the vent opening groove.
The thickness has never been broached yet due to the oversize. I think I could park one of my anvils on top to thin it out should that be the next problem.
Now to figure out that overwidth without going near a razor blade as that would just open a new can of worms.