After the fibreglass was set I started peeling off all of the masking tape and then peeled off the Styrofoam form I had made. The white glue acted as an excellent barrier both preventing the resin from eating or dissolving the Styrofoam and made for a smooth inner surface, not that anyone is ever going to see it lol. I trimmed off the rough edges with a coping saw and filed them down a little.
Next up was do do a little test fitting of my newly formed cover plate to see what kinds of additional adjustment I am going to need to make. As you can see on the curved part of the dash I will need to file down and then add in some more fibreglass and resin to make it fit more flush with the edge of the dash. Overall though it is coming along much better than I though this project would. Once I get my cover plate to fit nicely around the edges I can sand the exposed side of the cover plate smooth and then it should be ready for priming and painting.