I am amazed at the efforts you are putting into documenting excellent faceting history! Your series of web pages are most valuable…please keep up the great work!
A link on your own website to the following publication, might produce the oldest documented gem design I have found to date. It is:
A Study of the Reflection and Refraction of Light in a Diamond
by Marcel Tolkowsky, B.Sc., A.C.G.I.
with 37 illustrations
E. & F. N. Spon logo
London: E. & F. N. Spon, Ltd., 57 Haymarket, S.W. 1
New York: Spon & Chamberlain, 120 Liberty Street
Contained in this document, by Marcel Tolkowski, are diagrams of an SRB with very specific, although somewhat complicated, angles for faceting. I would consider this a complete, documented design, dated 1919. This entire Diamond Design Study is completely fascinating to anyone interested in seeing the details of how Marcel Tolkowski worked out the proper design for an SRB.