CABOCHON SHAPE DIFFERENCES

These four show some of the different shapes used on the "roundels" or "enamels" of the period. I think there are two Ruskins on the top row: the hexagonal is marked but the mark is obscured by the "plaster" (?) of the second. This second one has the clean glaze finish and the thickness of a Ruskin. The bottom two are from an unknown factory.
Interestingly they are glazed all over and have distinctive 'stilt marks'. Each one was placed in the kiln on stilts. I have a quantity of cabochons from this factory. They are much thinner than the Ruskins. The label too has me perplexed. It reads "2430 / No 196" in ink script. Another cabochon from this factory has a "4" on its base.
Any help with attributions of this factory or any comments are appreciated.