Comparison between observed (gray) and synthetic (blue, green, red) spectra associated with the three sets of parameters indicated in Table D.3. In this figure, we concentrate on stars labeled as Q3, with luminosity class I or II, and where the fitting of Hα implies a higher value of log Q compared to He IIλ4686. Blue lines correspond to the IACOB-GBAT best fitting models obtained by considering the full set of H/He lines. Green (red) lines correspond to the higher (lower) log Q values indicated in Table D.3 for each star.