I don't think with 6" blocks you will have any stretchiness. It is when you sew on the diagonally from the weave (45 degrees), that is where the bias is. I am sewing some 14" long diamonds which all 4 sides are on the bias so I am being very careful to make sure the bias side is down when stitch. Figure my friend would choose an old Kaffe pattern. Good Luck.
