The featherweight takes a general low shank walking foot, some have used both new and old and it seems to work. The best might be to get a version made for the narrower feeddogs; they are sold on the web a few places like
Sew Classic, and feed back on them is generally good. The Penguin is nearly impossible to find, but the Swiss Zigzagger turns up now and then, so keep an eye out; it works well as a walking foot in the straight stitch mode.