I use Wonderunder and "window" large appliques. Windowing is when you trace the outline of the applique and remove all the inner part of the Wonderunder until you have 1/4 inch before the outside cutting line. This keeps even large appliques soft. I stitch down my appliques with a zig zag or buttonhole stitch and I will sometimes remove the double fabric under the window applique. A lot of people like Mistyfuse but I haven't tried it.