The research presented here is a continuing work in progress!
After many long hours of research, I've followed the trail of the "Pentacles of Tozgraec" about as far as it can go. Here's what I've learned...
In antiquity, there was a well known philosopher / mathematician / astrologer called Toz the Greek. Some have speculated that his true identity was merely a series of writers utilizing the Toz name, which, in its original form, might have been Hermes Trismegistus (a Greek) or even father back to the Toth of ancient Egypt. Both Hermes and Toth have been linked together and throughout history, there has always been debate about the divine origins of their prolific writings.
Toz the Greek's name was attributed to at least four books of his own written during the 1400s - 1500s. His sources appear to have come from further east and are rooted in Arabic astrological / mathematics traditions. Whether he wrote these books himself, or whether they were merely attributed to him may never be known with absolute confidence.
Now we come to the topic of Toz the Greek's name. He is called by at least three names, depending on the source and the language. In English, his name is generally rendered as "Toz the Greek." In Latin texts, he is generally called Toz Graec or Toz Graeci. And in French texts, he is generally called Tozgraec.
Author Guidonis Bonati mentions the works of "Toz Graec" in his book about astronomy De Astronomia tractatus X (1550). My Latin is extremely questionable, but I believe it's indicating the effects of the moon upon the human body and stating Toz Graec's opinion on the matter. Which would seem to line up with Toz's general area of expertise.
Later manuscripts (including several different Clavicles of Solomon) dating from 1600 - 1800 actually claim to have been written by Toz the Greek, although these anonymous works are mostly just re-hashed Solomonic spells and conjuring invocations that have his name slapped in the author slot. The earliest of these books that has survived is a Latin manuscript dated to 1601.
The Pentacles of Tozgraec
When summoning angels, the most common seals that are used are either those created by John Dee (Enochian magic) or those created using the method spelled out by Agrippa in La Philosophie Occult (1531) and later used to craft the Archangel seals found on the Magical Calendar (1582). These are, without a doubt, the most easily recognizable angel sigils currently in existence thanks to a re-printing of them by Robert Ambelain in La Kabbale Pratique (1951).
However, there is another set of seals / sigils known as the Pentacles of Tozgraec that are entirely different from the Agrippa seals. Nearly every grimoire accredited to Toz the Greek contains the same set of 72 pentacles designed to evoke the angels of the Shem HaMephorash.
Based on the style of sigil used to evoke the angels, there seems to be four distinct traditions for angelic conjuration in the old grimoires:
Toz the Greek
Each of these authors (or authors claiming to pass on their knowledge) has a different method for drawing angelic sigils. Which ones are "correct" could only be determined by experimenting with the different sigils and seeing if you're greeted by an angel or something horrible from a dimension beyond our own.
Either way, please use protection.