I don't even swivel my hips. I just start my swing about 45 degrees off my right hip and foot, arm straight, and drag the coil over the ground in an arc to about 45 degrees of my left hip, take a tiny step forward, and swing back too the right in the same arc, tiny step, and repeat. My path always has a slight bulge ahead of me from the arc, but my coil stays absolutely flat with no tip up at the ends and no ground is missed in the sweeps which are also naturally very comfortable and longer than one can comfortably make a straight side to side sweep. My coil is never very tight so it sort of rides flat over minor changes in ground levels. Of course this works best on surfaces where you can "scrub" the ground like lawns and beaches or grassless wooded areas. On cornrows in plowed fields and fields where the grass is in higher clumps I still swing in the arc but need to keep the coil a little tighter and higher to keep it level. I've been swinging for over forty years and find this way to be the most comfortable and efficient way to keep the coil perfectly level for the entire sweep. The longer arced sweep also covers more ground per sweep although it slows down the forward progress slightly. I also have my detector shaft at a length where my arm points fairly straight down to the ground at a slight angle with no bend in the elbow at all, which is a whole lot less tiring than having your elbow bent and trying to make straight swings ahead of you. This puts all the weight on your upper arm and shoulder, and never tires your elbow or forearm. Try it, you may like it.
