How to choose firmness: sleep position and body weight
A working checklist; deeper lab-style data and charts will ship in a later update.
Side sleeping
Shoulders and hips need room to sink; too firm causes numbness, too soft can bow the lower back. Spend at least five minutes on your side and notice even support from shoulder to pelvis.
Back or stomach sleeping
Back sleepers need neutral lumbar alignment; stomach sleepers usually need a firmer surface so the midsection doesn’t hammock. Higher body weight stresses support layers—check thickness and density.
Next steps
Use trial policies to rotate through two or three finalists for several nights. Morning stiffness and how often you wake to reposition beat a single showroom lie-down.