In school here,many shop students made ashtrays that were pounded into a wooden form.
The Plan.
Carve intended design to full depth in the wooden form.
Attach blank or sheet to top of the wood form, with screws or nails. Leave about 3/4. Inch all the way around the depression in the form, for screwing down.
Then start pounding and stretch the material into the form, then when it takes shape, get it as smooth as possible.
Trim the basic shape out of that, ie..cut off the holdown edge.
Then add thicker strips all the way around the edge, the strips will have mounting lugs attached and be soldered to main piece. The lugs will start off as a machined pointy bullet shape with a groove around it. Then flatten off the sides, and add groove to lock into grommet.
The mounting lug either has a flanged base to solder, or is drilled and tapped and held to mount with a button head.
Sounds easy , I will probably farm out getting the form routered out..