Thank you for this! My source for the Thema Mundi is the partial translation of Firmicius Maternus by Thomas Taylor that got included in one of Manly P. Hall's odder books; I'll have to doublecheck and see if the material on judging natal charts against the Thema Mundi is included there, and have a look at Firmicius Maternus more generally. As for Abu Ma'shar and his peers, they're already on the get-to list, because the great conjunctions are a branch of mundane work the classic mundane tradition I mentioned doesn't really do much with, and I want to give it more attention than I've done so far.