I use 80/12 sharps or microtex for piecing. The microtex are usually 70/10. Both are very sharp and there is no "popping" because they are so sharp. For Free Motion I use 80/12 or 90/14 Topstitch because the eye is bigger and eliminates the problem of fraying thread. I use embroidary polyester thread for Free Motion. I love it, it has a shine that really looks good.