The "317" is the smallest of the various bent Billiard shapes in Peterson's System shape chart. Dress finishes, such as the Ebony finish used here, always seem most appropriate to me when paired with smaller pipes. It's a finish appropriate for the opera or theater and, really, intermissions just aren't that long. So, a smaller bent Billiard in a dress finish just makes a certain amount of sense to me.
-- Sykes Wilford