Cast a block of lead, make a punch with the right form, dap this punch with a heavy hammer into the lead block.
After that you can dome the sheet in it.
I use a wooden Dapping Block set for most of my silverwork and stuff. I made a hydrolic press for the steel pieces (buckle blanks, spur bands, ect.). Go to Rio Grande's website and search "Dapping Blocks" that will pull up everything they have and should be most anything you'll need. I also made a little jig for doming the conchos that have the lip around the edge. It was pretty simple. I can send pictures and explain the process I used to make it if you want.
I guess I also wonder how you go about achieving the flat edges of say a concho (that are not domed). Is this achieved simply by using a dapping block? Also, how do you keep the piece from being scratched by the metal dapping tools?
It would be best for you to get to a shop and see the tools in use. If you can't get the tooling then send the sheet silver to one of us and we can dome the silver for you. If I were to start over that is the path I would take.
Yes. First buy a kick or screw press. Then buy the metalworking equipment. Then buy the metal for the dies then make the dies. It is all available on the Internet. It is much easier to send your sheet to someone and tell them what you need.
I make a lot of jigs from wood and my dapping blocks and punches are wood, turned hard maple leftover from a muzzleloading rifle or two. I use a small rawhide mallet for a lot of forming but I also use fairly thin stock 20 - 24 ga. typically. I wood lathe helps to make some punches but the holes I gouge out with a wood carving gouge and scrape smooth. Good luck in your venture.
Mark