Hardly anybody copies the lead spacers often found on old razors, but it is true that the original makers knew what they were about. You can temporarily bolt or clamp two thin strips of metal to the tang (with the blade in the open position), insert a spacer half-way along if you think one is needed, and a piece of sheet lead at the rear end, then use a vice to squash the thing into the right shape.

I also like the wedgeless construction we sometimes see, with a single joint in line with the edge, and contouring of the inside of the scales used to give clearance instead of a wedge.