Half-light-radius variations in the radial emission as a function of wavelength for changes in the parameters that have the most promising impact on the photometric and interferometric observables (top and middle) and for changes in the dust composition (bottom). The hlr were calculated at the central wavelengths of the H, K, L, and N bands. The geometric model data points are taken from Corporaal et al. (2021). Top: effect of changing α (left), ß (middle), and h₀ (right). Middle: effect of changing m_d (left), q (middle), and r_mid (right). Bottom: variations in the DIANA parameters (left), the crystallinity fraction (middle), and the metallic iron content (right).