30 Ford header

I'm putting the body header on my Model A. Everything fits pretty good except at the top. The metal piece on the front of the header that covers it is about 1/8" shorter than the wooden header. There was nothing there, so I have nothing to refer to. The visor lays over the top of the header and I assume the these two pieces join to provide a seal against the elements. I hope I described this accurately enough. In other words, when you look at it from the front, the wood sticks up 1/8" higher than the metal "Flashing", for use of a better word. Does anyone know if this is correct? Does the flashing piece have to meet the visor flush? I'll try to get a picture to help out. I've looked at a lot of A's and I'd like to somehow overlay this area with fiberglass to ensure a weather proof seal. Does anybody have any recommendations or websites to refer to?

Here is a picture of what I was talking about hope it helps. Thanks in advance everyone!