I don't know if this will help, but I am planning on building my own Overhead consol. I have just started getting the basic materials together, such as; Bailing (baleing ?) wire, thin light weight sticks (straight), tape measure, and a couple of thin (but sturdy) sheets of cardboard. I will figure out how far out from the windshield I want the consol to be, then wrap a length of the wire over the top of the cab, and across the inside roof. I will then place a second wire closer to the windshield. with this in place I will be able to take the sticks and lay them from one side of the cab to the other about an inch apart, mark them where they cross the first wire (Front of consol) and then lay them out on a piece of cardboard in the same order. This should give me a fairly accurate pateren <wish I had a dictionary handy> for the bottom of the consol. The front of the consol will be done about the same way, but without the use of the sticks. A small rigid tape measure or a thin (width) ruler would do just as well, measuring inch by inch across the width of the cab.
I would rather find someplace that still made the original wood paneling type of overhead consol, as, I cannot afford the newer Plastic or Fiberglass consol that are being sold now.