I hadn't studied the links given above before now, but they make interesting reading. How is use of the equipment progressing?
As an aside to the present question, when British .500 silver coins became cupro-nickel in 1947, a finer edge graining was used. Unfortunately, when the silver content was changed from .925 to .500 during 1920, there was no such indication.
Apart from the early .500 issues (until about 1922) turning a slightly yellowish colour, there is no visual indication of the silver fineness. After about 1922, a better alloy mix was devised.
Bill.