Do whatever works best for you! I lower my feed dogs because I was taught to do that. I seem to break fewer needles with them down though. I FMQ 90 miles an hour once I get going and if the feed dogs are up, there is more resistance. With them down, I can get more swirlys and smoother loopys and it doesn't appear as jerky. A lot of FMQ involves moving from side to side as well. With the dogs up (which only pull in one direction, to the back), moving from side to side is much harder. Hope that makes sense.