Some exciting news! I received from the Jewish Musuem of Prague scans of the so-called Fassionen, or family record pages. These are the sources for the 1748 census book that was published several years ago, but they extend well beyond those years. The 22 books of Fassionbücher (1748–1838) contain 4749 scans. See https://www.dropbox.com/sh/6wq3imxmid8fywv/AADZDypli-YGvJhxP_CJj1gr...
These should help us fill in a lot of the gaps, especially since the ones after 1748 often include the wife's father's name. We've had some trouble with people born after 1748 who marry before the record books start in 1784. These Fassionen records will also help a lot with those as well.