I use the same top and bottom, and none of my machines are fussy most of the time I use the Coats and Clark (I know, it is poor quality and turns out to be expensive) but I can get it in a lot of colors and not have a bunch of it sitting around when I am done. So that is my go to. I do have aurifil that I use for piecing sometimes. I have used sulky variegated for FMQ and that works okay.