I know basically how they were made and the exact metallurgy. I have not made any but dream of putting some together someday...

I have a Fauneta. So my primary interest is in the 20. I looked at a Manton's catalog from about 1920 and noticed the Fauneta ammunition was the same price as the .600 NE. If Westley Richards only offers loaded ammunition, I'm not really excited about buying a bunch (not to mention that the 2 year estimate likely laughable).

What is the level of interest here? What do you need, 20 or 12 (or 8) bore LT Capped?
Can you make tooling? Do you have a spinning lathe? CNC spinning lathe?

Maybe there is enough interest to get this done.