“They let their beard grow long, but they shave their moustache; they wrap themselves in loincloths, the bringes of which they have made long, but they forbid the wearing of “t”aylasan, and laugh at those who wearit, calling them the followers of female magicians (sahirat). They themselves wear shows and loincloths four cubits long so that the fringes drag behind them when they walk. They make dots in each corner of the cloth, four dots of saffron in each corner. They also plait their hair in baths and dye it with henna, wear blue or green turbans which they wrap around their forehead. They fight and compete in argument with each other. When they wal or spea with someone, they try to make you think that they [never?] look at the sky, ing afraid of the gods…they dedicate themselves above others to the star of Saturn [note by D: this may mean Perseus, not the planet]. (p.296)

A couple of points, just in case this thread is taken up again by a linguist. In Arabia, there is a notable S-T shift in inscriptions from Arabia deserta. It was documented by an epigrapher named Bill Jobling, who worked from Syd.Uni, but sadly died (with much unpublished) in the early 90s. I expect others have taken up the matter since.

Also, in the Nabatean Agriculture, Ibn Wahshiyya refers often to the people called (in English) Sethians or Seth-ites. The same cult has been described in numerous publications issued by Brill, showing its widespread influence in pre-Islamic times.
Google: Seth AND “published by” AND Brill.

So it may not be “Siit” – about which I can find no reference at all, but a female manifestation of Seth (is this our manuscript’s bearded woman?) worshipped in the near east during pre-Islamic times. If we are looking at the Yemen and the coastal regions, a strong Jewish presence is quite to be expected for the late classical – Islamic eras.

I’m concerned about possibly having stumbled over the same things about which he or she might have written somewhere, at some time, under … what name?

Personally, I don’t think there’s any Sufi influence on the VMs – for all its pecularities, it seems to be a tree grown in distinctively European soil. The furthest East I can get is that it seems influenced more by Byzantine herbals than by European herbals. But there have always been other opinions on it, so what do I know?