What's the best cervical pillow for side sleepers versus back sleepers?

Reviewers generally favor a higher loft and firmer support for side sleepers to fill the shoulder gap, and a lower contour for back sleepers. Adjustable-loft models (such as the UTTU sandwich design and the Osteo hollow-fill pillow) draw praise in community threads precisely because they let you tune height to your position, which matters most for combination sleepers.