You may want to try John F. Allen & Son in Providence. The phone
number is 401-421-8219. The catalog I have is a little old, but they
should still be around. Another source I used before is Pulver in New
York City. I’m sorry I don’t have their number but they are listed.
They are either on 37th or 38th street in Manhattan.
How about using some old buttons? I also did that using vintage
buttons and grinding the back flat.
Best of luck to you, Vera