Drawing this angle

At 157.5 degrees, the head is almost facing directly away. The visible ear and the unequal widths on either side of the rear head mass give the small turn its direction. Place the back of the skull first, then compare how far the ear projects beyond that shape. Keep any remaining cheek or jaw detail small enough to agree with what the plate shows.

Look at the junction between the neck and the underside of the head. One side may be easier to follow while the other is hidden by the skull. Use those overlaps to place the neck behind and beneath the head, rather than attaching a centred tube to the lowest point. In the tonal study, keep the broad rear surface connected even if it contains several value changes. Make a simple contour sketch beside the 180 degree view and identify the few differences that explain this slight rotation.