I know that many of your are anxious for your book to arrive so that you can figure out what you need. If you're hoping to pull from your stash, here are some basic fabric requirements for each size of the quilt. Please note when making your color choices that each version of the quilt has the darker color in triangles around the entire outer edge. This not only brings the eye into the quilt, but effectively makes it a "border". So no matter what color choices you make, be sure to think a bit darker for the outer edges.
The smallest is the lap size/baby/throw/wall version ... it measures 59 1/2" square.
Background fabric - 9 fat quarters
Primary dark color - 18 fat quarters
To add a third color, you will need 12 fat quarters of the primary dark and 6 of the third color.
To add a fourth color, you will need 12 fat quarters of the primary dark and 3 each of the third and fourth colors.
For example, black, white, red and gold ... black 12/white 9/red 3/gold 3
The middle size is the twin size which measures 76 1/2" x 93 1/2"
Background fabric - 22 fat quarters
Primary dark fabric - 22 fat quarters
Dark fabric for side triangles - 7
To add additional colors, I would suggest at least 3-5 fat quarters each of your contrasting colors.
For example, my lime and turquoise combinations from the photo below will have a cream background (made up of an assortment of creams), and I will be using both turquoise and plum as accent colors. I have an assortment of limes totaling 5 yards (20 fat quarters), 2 yards of my fossil fern in turquoise and lime (8 fat quarters), and a smaller pile of 10 fat quarters in plums and turquoises. My fossil fern in turquoise and lime will also be my fabric for the side triangles.
The largest size will be the queen sized, which I'm calculating measures about 93 1/2" square. Math isn't my first language so if anyone else has the exact measure figured out, please share it! Making up the queen size is adding another extra row width-wise and you'll need another 25% of your chosen fabrics ... so 5-6 additional background fabrics and 6-8 additional fabrics.
Hope this helps as you get ready for this great project!