The feed dogs don't have to drop for quilting, just set the machine at no stitch or 0 stitch length. What kind of needle are you using in your Janome? Perhaps a different type, as in Universal, or top stitch, or embroidery or something along those lines would work better, sometimes the hole size will make a difference with the stitch so I change the needle on my Janome Kenmore. I use Schmetz and have a variety of needles available.