I did this with a set of Gay Paree plastics. The nice thing about these old Williams plastics is that they are printed on top and the background is white. There is no easy way out. The ones I did just barely fit a standard 8 1/2” x 11” scanner. Scanned them and used old paintbrush software. A lot of detailed work. Once done you can print them on photo quality paper, just make sure the paper is not water marked so it doesn’t show up when back lighted. Attach to new plastic with clear spray adhesive. Overcoat with Triple Thick. You can get the plastic sheets in home improvement stores. They have held up for 15 years.

One more thing to note: these old plastics then to shrink. I rescaled mine a few percent to get the right post spacing again.