I mailed out my F8's yesterday. I sent 2 - one of my focus and a coordinating fabric - with a note that says please use these two fabrics and that if you absolutely need to add a 3rd color/fabric, to please add only medium/dark browns.
I hope that doesn't sound too overbearing - it's just that I have a really specific vision for the layout and color and since my focus fabric isn't available anymore, I want to make sure I can use each & every block.