The upper and the middle panels show the synthetic spectra (dotted black lines) of HD 66811 (left panels) and HD 15570 (right panels) obtained from the PoWR models, i.e. without macroclumping. Thin solid blue lines are observed spectra. The dashed green lines in the middle panels are from the same model, but only accounting for the photospheric lines while wind lines from P v and Si iv are suppressed. These photospheric spectra are used as input for the 3D Monte-Carlo calculations with macroclumping (lower panels). The parameters of these models are given in Tables 1–5.