I FMQ on my FW. What works best for me is 1) set stitch length to 0, 2) follow Leah Day's suggestions here:
https://www.youtube.com/watch?v=B47GtkFIbaU 3) I've done it with and without covering the feed dogs by taping a card down, but can't really tell the difference.....although my stitches seem to be more consistent if I leave the feeddogs uncovered