Rose_P

I have used them in a few quilts. I would steer away from patterns that have a satin stitch or other very closely spaced stitches because they might act like the perforations on a stamp and weaken your quilt. If it's something that isn't going to get washed, that might not matter.

I don't know about Necchi, but the instructions with every walking foot I've seen say not to use them with any stitch that backs up or is wider than a regular zigzag, which may be most decorative stitches. Test the stitch you want to use by using the recommended foot first (on a layered swatch) and watch to see if the fabric goes forward and back and/or side to side. It won't be able to do this properly with the walking foot. If you first use other types of quilting close to the area where you want to do the decorative stitch, maybe it will work okay without the walking foot. For example, you could quilt everything except a narrow border, and then add a line of decorative stitches in it. Hope you'll show us the finished quilt!