Keith, you need to refer to Chapter 3 in Chance Expressions, as this shows all the sizes and shapes. However, this is not cross-referenced to any particular pattern, but what was available at any time. The problem I had is only having access to 1954-57 export, 1969 and 1976 catalogues, which did limit me somewhat.
The 12-in diameter plate is certainly a biggie although it appears in the 1976 catalogue as a 13-in tray (No.33). The largest plate is 10-in (No.55). I'll mail you a scan.