I do them as narrow as I can fit the bell between my legs. But lots of people do them with their widest comp stance or wider. I'm with Jim, just swing away and make them happen. Any stance will murder the glutes and hams, wide should hit the hips too. Hell, narrow got my hips pretty good due to the violent external rotation force. You can probably even put a mini around your knees for swings since all swings should be done with the bell as near your genitals as possible
15Th edit: if recovery is still an issue, you could do sled walks holding the harness by your crotch with a band around your knees, too. Doesn't hit the hams as well as swings, though.