Nice work!

Since you are using RTV 1898 Panhard et Levassor molds, you can put pins, wire, into your pattern, and later use the cavity that they create to hold your screws. Casting 1898 Panhard et Levassor resin 1898 Panhard et Levassor into such a mold will capture the heads of the screws and give you the studs. -if that is what you were intending?

Again, very nice work! Any more progress to share?

-Don