Comparison of strategic H and He lines in the optical, for all models from our grid. Black: FASTWIND v11, green:  CMFGEN, red:  FASTWIND v10, with no blends from other elements. The marker in the lower right indicates a wavelength range of 20 Å, and a vertical extent of 0.5 of the continuum. To enable a better comparison, the spectra have been convolved with a rotational broadening of v sin i = 80 km s⁻¹, and degraded to a resolving power of 10 000.