Hi, Carla. Yes, 57 because that's what it narrowed down to when I came up with the list of all the spread positions to include.
The set will be coming out in March. The guidebook contains information on how to craft a spread and different ways to use the cards. Like you said, it's pretty self-explanatory, but not everyone has crafted a spread before. Plus, the cards will be color coded for use in my spreadcrafting system (basically a system that makes spreadcrafting easier for beginners and those who want to follow my way of spreadcrafting.) So if you want to know what the colors mean, you'll have to look in the book. And I may also have suggestions of ways to use the cards in the book that you haven't thought of. Certainly many on this forum will be putting them to use right out of the box, however, and won't have to read the book.
I have seen the box design, which has a picture of the cards in use on it. So that's all I've seen of the design so far. Sooner or later I'll have to finalize the copy on all the cards, so I have no doubt I'll see them at some point. I suggested a size of roughly 3x6....wide enough to fit the width of most tarot cards and tall enough for the spread name to poke out the top. Clearly, the cards won't be bigger than a Rohrig, for example. But I have a pretty large collection of decks and there are only a few that are either taller or wider than the spread cards.