I would take the factory plate and glue some thin plastic on the back but leaving the radio shaft holes open. Find two large short carriage or flat head type bolts to put through the front through the holes for nuts and washers to snug up on the back. Epoxy the bolts in and apply a layer of plastic body filler in thick enough to fill in smooth out over the high spot. After it cures, mask the chrome edge around the outside edge and sand smooth using a piece of wood the size of a matchbox to work it with. Repaint with argent gray to match the heater control bezel. You can tell it's winter and penned up inside again, too much idle time to think about doing busy work. You might could use a Dremel and trim down the two raised bevels around the radio shafts to make the build up thinner but it's kind of awkward to do.