I don"t Know any thing about how to run a computer. If the scrap flange comes from the wheel you use the old spokes may fit . grind punch to fit holes in flange. (I am a tight wad who has never done this.) James Newton IA
I would center punch the spot where the 5/8" or 3/4" axle hole will be. Then I would use a set of dividers to mark the outside circumference of the flange. Center the scrap flange on this, clamp it and drill away. there would be no need to center punch the 18 spoke locations if using the old flange as a jig. You could drill all the spoke holes and the axle hole before cutting and shaping the circumference. This would make the material easier to hang on to while drilling.
Paper: Something that folks used to draw on before computers came about and created even more paper, but with printing on it instead. Heck, making the paper these days is even controlled by a computer.