After much sanding and even some more glass work the cover plate is getting to fit the form of the dash much better. I "Bull-nosed" or "Beveled" the outer edges close to the front of the dash. I still need to add a little more glass in one area where it looks like the only place I will be able to put a screw in is one of the Aluminum brackets holding in the electronics because it is in an ideal position for a mounting screw.
You can see that from the front view the underside cover plate should be pretty hard to see once it is finished, primed and painted. But I am a ways away yet. I still need to do a test fit of the dash again and see how far back towards the stock OEM dash that I may need to extend the cover plate. I also need to glass in an Aluminum "L" bracket to the dash on the far right of the dash to be able to screw in that end of the cover plate too.