Hi Carol,
On the 930, I would use a zig-zag stitch to applique. Not a satin-stitch, just a medium, loose zig-zag. Stitch length about 2, stitch width about 2.5. And I use thread that matches each fabric on the top, but use a dark taupe in the bobbin for all. Taupe blends with just about everything.
I did trade-up my old Bernina 1030 for a Bernina 230, just to get the blanket-stitch for machine applique!
The serpentine stitch is #8, and is great for machine quilting. I highly recommend the walking foot for machine quilting. It works great with straight, zig-zag or serpentine. I set the stitch length to about 2, and the width to as wide as it will go. The serpentine stitch is especially good for poorly pieced quilts. If you sew over the seams with a serpentine stitch, it will help strengthen the weak seams. Or, if the quilt is simple, and doesn't need fancy quilting, the serpentine is great for that, too.