I use a blanket stitch too. The straight stitching goes on the background fabric just outside of the piece to be appliqued. The tacking stitch goes into the piece to be appliqued. My Janome 6600 has a blanket stitch with a double straight stitch so it makes a thicker line around the edge, which I prefer. I find that it's easiest and neatest to pivot around a curve with the needle down in the tacking stitch.