Beautiful quilt!
I took the class to learn to use the tool. Used a Moda charm pack. Teacher said to lay out a pleasing array so lights and darks alternated. It was okay, but I would have liked different fabrics to have ended up next to each other in the final product.
The trick is in how you lay out your squares. I want to know "the pattern" for sewing the squares together that will result in pinwheels like yours- all looking nice against the ones next to them. I can't seem to visualize how you have to sew the squares together to make that happen.