2 pointsI made a set from aluminum long time ago for a set of wheels I had. And made a set from steel for the Magnum 500s I currently have on the car. Can't remember the alloy I used (6061 possibly) but aluminum was fine. Used whatever material I had laying around. If you find the right size of steel tubing, you do not need to remove a lot of material (especially from the inside) and should be able to machine it on a mini lathe with small passes. Or you can get 2 different sizes of tubing and slip and weld them before machining. That is what I had done with the Aluminum one, the lip was welded/machined.
1 pointNext step here is to take the door, lock out, and somehow painted, or coat it back. Actually have a set of door lock cylinders from late 1980s Mustang, that are black from the factory, I’m gonna try to install those. Not sure if they fit.