I am FMQ'ing on my PQ Brother 1500 S these days and I use nothing but Bottom Line in the bobbin, which is vertical on this machine. Most usually, I need to adjust the top tension lower to get the stitches right. I use the same thing on my Kenmore/Janome 19606 horizontal bobbin, (no special case for this), and the same thing applies, have to lower the tension somewhat on top. Top thread, I use whatever, many different brands and varieties in topstitch needles. I am so grateful that this machine has no gourmet taste when it comes to thread. I love each of these machines for FMQ, depending on the size. The Brother has a much larger harp area, which is why I bought it. It is a straight stitch machine only.