I signed up for Amy's BOM for next January and got her email about using Kona solids. I've used Kona solids and found them to be pretty thick. I am going to be using them for her class also. I am going to be copying Amy. I did her Craftsy BOM and used the same fabric as she used and really like my quilt.
But, I also bought a lot of 1/2 yards of solids from Connecting Threads and I think I might use those instead. I bought a few yards of grey, which she said to buy, and I have a few yards of Kona white, which she suggested, so I'm set to go with her class. But the Connecting Threads solid fabric is pretty thin compared to the Kona Solids, so I'm not sure which I'll use yet, but I'm using solids for sure. Since it's a mystery block pretty much, I want to do what Amy is doing.