I just left a note about procuring source materials, on your talk page.  

Also, with reference to your mention of Cassini's tables, you might like to notice that the practice about 'signs' in the eighteenth-century tables was to treat a 'sign' as just a superior unit of 30 degrees:  this is shown by the presence of this unit also in the tables of increments corresponding to periods of time, and in the tables of angular differences (such as mean anomaly), these usages show that such a 'sign' did not need to begin at any particular place, it was just any arc of 30 degrees, a practice also mentioned as occasionally occurring in ancient times, I think, by O Neugebauer in 'History of Ancient Mathematical Astronomy'.