Trax,

Nice project!

You can lay a piece of plastic bag, black, over that entire area. Tape it on the other side so it is pulled drum tight. You can then lay light glass cloth over the plastic bag piece. Lay the glass cloth down, saturate it with resin, then place another plastic bag piece over it. Pull it tight like the first one. one layer could do it. This will give you a nice fiberglass piece that will fit perfectly. And after trimming, can be put in place with screws. I use Polyester resin. Repeat the same process on the other side. Might take two evenings, but what the hell.

Or. Sig makes a material that comes in sheets. You wet it. Forgot with what, cuz it's been ages since I've used it. Dries to the shape. Sig's deal is easy as pie. If they still offer the stuff?

Ever hear of gold leaf? Well, there's aluminum leaf. Google it. Easy to apply and looks like the real thing cuz it is!

Whatever you decide, good luck.

Charles