Hi, and welcome aboard. For piecing my blocks, I use Aurifil only, as I think the seams lay flatter after pressing, either to one side or open. I use either a 14 or 16 needle for piecing and machine quilting. I use Connecting Threads poly thread for quilting the top which is mostly done in a grid pattern as it's quick to do and the majority of my quilts are donated. I do use a size 16 needle tho when I do paper-piecing as it helps when tearing of the paper.