As a Machinist
I am just suggesting to the Idea's
Is it feasible to add a Rolled Bead a 1/4" back that the grommet that would seat in?
For sure there would need to be 15 degree (or more) Included angle ,
So it would not pull it thru and still be able to tighten up to the Exterior body panel.
Are you designing this with a NOS filler neck grommet?
