If you cannot obtain a brass rubbing of an original, please see below for a possible approach.
There are catalogues for both the Elliott and Victoria dividing heads here:
http://vintagemachinery.org/mfgindex/detail.aspx?id=10615
Both contain end elevations of the head, showing the banjo.
Photocopy the page and enlarge it to 1:1 scale based on a known dimension of what you have. Cut out the shape of the banjo and glue it onto a piece of metal. Hacksaw, file, done.