I thought of something regarding the 1817 Jola from San Antonio - the two straight breaks along the edge suggest that the flan might have been one of a number, cast in a line, then broken off for coining. Ancient Jewish bronzes were often manufactured in the same way. There's a French term, en chapelet, for this kind of process; the word 'chapelet' refers to something in a series, but it can also mean a rosary or a string on onions!