What wavelengths should a red light panel have?

Most reviewers point to 660nm red light for surface/skin benefits and 810-850nm near-infrared for deeper tissue and joint penetration. Specialist-community commentary in r/redlighttherapy notes that 660nm is excellent and that 810nm/830nm near-infrared is considered better than 850nm, which one poster called only 'acceptable.' Multi-wavelength (quad-chip) panels that add 630nm and 810nm cover more bases but cost considerably more.