I recommend you use what ever weight and brand of thread gives you the look you want. I use Aurifil and Prescencia for piecing and Aurifil, Mettler, King Tut, Wonderfil, and a couple of others in weights from 50 down to 28 for quilting. Sometimes I want a finer thread that doesn't show too much and sometimes I want a bolder thread that stands out more. Experiment.