In my experience the astrological association with the cards was so very different than any I am comfortable with, it was hard to follow. I am more inclined to understand, if not always follow, the solar decans. I had to spread out her zodiac wheel chart and try and figure out which card went where and would be constantly having to look up where the cards went.. it was not 'logical' to me.
That said, it is a lovely deck and it is clear she spent a lot of time thinking out her own system which this deck follows.
Solandia does a good job of describing the deck:
Unlike a typical linearly-organised tarot deck, these cards are ordered to correspond with lunar cycles, seasonal festivals, and zodiac associations. Thirteen majors relate to the thirteen full moons, eight majors to the cross-quarter days in the Celtic calendar, and the remaining card, the World, is the central card in the cycle. The Aces are linked with the seasons, and the rest of the minor cards, rather than being connected with the 52 weeks of the year, and connecting with the lunar phases. (The book has a pictorial diagram that illustrates the placement of each card in the complex pattern.)