I hope this will help, the visor slides over the top side iron ,and the cap and screw on the side hold the brace. The piece the visor is made from was 9 1/4 wide and 48 inches long. The flat part is 43 inches which is the distance on the outside of the window irons. It looks like 2 1/2 inch was bent at a 90 degree angle to provide the side support, and then cut at a tapered angle.The front of the visor has a "drip strip " across the 43 inches, must be for strength. It looks like it was welded on but it is absolutely seamless. Only wish I could do metal work like that.
The back side of the visor had the center 40 inches folded twice approximately 3/4 inch each time, this makes for strength on the back and room for the windshield wiper, it also was bent upwards in the middle about 1/2 inch must have been for drainage.
I had a real challenge getting it over the top posts as I had replaced all the rubber gaskets in the windshield. I did it alone but only because I couldn't get it back off after I started, definitely a 2 person job especially after a high end paint job.
I had helped install several model A tops for some friends but never tried one from scratch. The only places that would make a top were 50 miles away with a year wait, it was a challenge again, I had some upholstery experience and that was helpful. The old top made a good pattern but over time the old vinyl had shrunk and I wish I had allowed more for the shrinkage. I have been asked several times if I would attempt another, they couldn't pay me enough. Although I would attempt one for myself.