Variations in the SEDs and visibility curves for the most impactful parameters. From left to right: the reddened SEDs, H-band squared visibilities, K-band squared visibilities, L-band squared visibilities, and correlated N-band fluxes. The SED plots zoom in to the area of interest (i.e. in the wavelengths for which we have IR interferometric data) to highlight the changes. The reddened stellar photosphere is depicted in brown in the SED plots. Here, the wavelength regimes of the H, K, L, and N bands are depicted by the vertical grey areas. The reference model is always depicted in blue. The visibilities are calculated at synthetic baselines from 1 to 150 m. Interferometric data are only shown around the central wavelengths of the wavelength bands. From top to bottom: variations in α, β, h₀, q, m_d, and r_mid.