sounds like a good tactic.
My concern would be that the gorilla glue would expand differently that the rest of the dash and give a weird "wave" effect.
Let it cure for a while, then stick a heater near it to see it you can notice it rising up in a weird fashion. If you can feel it when you rub your fingers over it, then it will end up showing through the coating.
Other than that, it looks good to me.
When you get it all done, you need to invest in some of that 3m window tint that blocks all of the heat transfer and UV rays to keep it from getting damaged again.
this stuff - Crystalline Automotive Films - Clear automotive window film for cars, trucks - Crystalline - 3M USit is awesauce. They have a 90 with is pretty much totally clear. So it is perfect for windshields.