I don't know why I was limited to a 3DPrinting forum, but oh well.
I managed to grab a much coveted Meyer's No.58 Movement holder off ebay, but it only came with the second to smallest jaw inserts.
Not to be detered I reverse engineered how to machine the jaw inserts.
Here is the Flickr Album.
https://flic.kr/s/aHBqjAGuFJ
I made a small insert set as a test and then made a set for size 16s pocket watches.
I'll make a few more to fill out the set.
I made these from Aluminum, but might try glass-filled Delrin as an experiment
The drawing could easily be used to design the jaw inserts for 3D printing in Nylon or a hard Urethane