OK, we are almost there. I somehow neglected to get a photo of “the Big Stab” where I attached the scalloped edge to the header with a single screw. (I am going to blame it on getting distracted by an incoming phone call.)
This is where the top fits after locating the single screw and latching the header for the first time. Its not terrible, but it could be better. I still want the drip rail to end up a little farther forward. Side-to-side, we are looking good. The header is not visible below the top material, but its not so tight that the bound seam is hanging too far below the header, which would cause the window frame to drag on it as it goes by every time the door is opened.