There was an episode on Sewing With Nancy or Simply Quilts many years ago. I cannot remember who the guest was, but she used a double needle with free motion quilting. She was quilting a landscape quilt and showing how the double needle filled in the area so fast (and well). Wish I could remember who the guest was and remember (for sure) what show this was. It could probably be searched for in youtube or googled by now. :-)