Slimboyfat, I cannot find sources for Fred Franz's Jewish scholar friend. I think I trawled it up recalling an assembly speech by him (approximately two centuries ago) where he mentioned his friend...as I recall, in warmly appreciative terms with me noting at the time the incongruity of him having a close worldly associate.
I also remember looking at the material which Fencing mentions where Furuli and others gave a numerical value to the accuracy of the astronomical evidence for 607BCE. This needs re-visiting and clarifying.