I do a whole lot of scrappy quilts. Rarely do I do something that is organized. I let the fabrics drop where they are some times there is a darker one next to a very dark or to light or medium dark along side it just depends on what is coming out of my basket next . The only thing I will do is switch out if the same fabrics come out along side each other. It is amazing how they come out just right. I just finished a scrappy top this morning. I had to add a new color in the last row that had not bee used before. Because of the scrappy nature of the quilt you would never know that this fabric was nowhere else in the quilt
Use your squares anyway you want. these squares are great for borders too. You have nothing to lose.