Thanks for your input. The backside ie. inside the cowling "dimple poke through
around the hole" I thought could also be epoxied with some build-up so that the
tinnerman is that much more secured in place around the inside surface as well.
I'll give it a try with straight epoxy and cleaned surfaces. I was sort of
thinking that someone should invent a very nice snap together or screw together
front and back tinnerman washer just like the other types of cowling fasteners
but have a nice finished tapered stainless steal screw appearance. I hope I
haven't confused you..Thanks for your input.

Larry