I'm sure this has probably been discussed on here, but, couldn't find the answers I am looking for. What is a good weight of thread to use for machine piecing and FMQ? Also, which will hold up longer to washings polyester or all cotton? And for the cottons, should it be plain or mercerized? Lastly, how are thread weights graded? Is 30 thicker in diamater or 50? I hope you can understand this. I'm so confused and hope I haven't totally confused you. I want to spend my money wisely and not waste it on alot of thread that I'm not going to use. I need you help in the worst way. Or do I really need a shrink? HEE HEE!!!