I use invisible thread often for appliqué. I use Aurifil monofilament from Superior Threads, it is great thread. I use regular thread in my bobbin that is usually just a neutral, light or medium gray or cream, depending on the background fabric. I use a blanket stitch for my appliqué most often, really don’t like satin stitch and don’t know how it would work with the invisible thread. Once in a while I do use a small zigzag. I also use the same Aurifil invisible thread for quilting. I do have to loosen my top tension a bit when using it on my longarm.