I have just finished reading DuQuette's companion book for his Tarot of Ceremonial Magick. I saw it in a shop and thought it looked interesting so I bought it with the idea of re-selling it. When I got it home and started reading I discovered it is a treasure trove of useful information, not only for his deck, but the Hermetic Tarot and Crowley's Thoth, especially with regard to the minor arcana. For example, each of the Hermetic minors 2-10 have two Hebrew words on it. Sometimes they are hidden and you have to look close to find them. These represent two angels of the Shemhamphorash. Each major arcana has one similar Hebrew word which I suspect are also angels but they don't seem to correspond with Duquette. They might be from the Golden Dawn. Anyway, this is great book for not only the Hermetic, but Crowley's Thoth. Lots of info.!
Edit: There is a mandala in this book that shows clearly how all of the Tarot cards correspond to wheel of the Zodiac, something about the Hermetic system that has always baffled me. Now it makes perfect sense.