I use 80/12 for piecing with Precencia 50/3 thread. Sometimes I use Aurifil 50/3. I personally think 2 ply thread is too light for piecing. That is the reason for the 'skant' 1/4 inch seam. I like to use it in the bobbin when I FMQ with Sulky or King Tut from Superior on the top. Then I use a 14 topstitch needle. The thread never shreds when I use this combination. So, if you are buying needles I would recommend getting a variety of needles. They really do make a difference. I have always thought that many of the problems some of you say you have with thread has more to do with needle selection than the thread.