You might want to try Arcana Mundi: Magic and the Occult in the Greek and Roman Worlds: A Collection of Ancient Texts by Georg Luck. It's an edited and translated reference collection of primary texts related to the occult and magic in the Ancient Mediterranean world, as it's title would suggest. The book is arranged topically, with each section being devoted to some aspect of Greek or Roman occultism such as Divination, Alchemy, and Astrology. Each section is prefaced with an extensive introduction with citations, and the texts vary from passages from Homer and Plato to inscriptions found on tablets (some being curse tablets similar to what you linked in your post). Each of the texts is also preceded by it's own short introduction which gives the context.

Unfortunately, as it's an academic text, it's somewhat expensive to purchase, but you might be able to find it an university library or through an interlibrary loan. You can look at a preview of it here on Google Books if you want to check it out before committing to finding it.

The Leyden Papyrus W is a 3rd C AD Greek codex, of a batch from Thebes/Uast. Papyrii A-U are on law, and V-X on alchemy. X could actually be called a chemical text, dirt practical. W has a lot of astrology and Judeo-Gnosticism, right up your alley.