Effect of microturbulence adopted in the NLTE calculations, v_mic(NLTE), on the strategic HHeSi lines for a model with typical parameters for our targets: T_eff = 32 kK, log g = 4.1 dex, Y_He = 0.1, ɛ_Si = 7.0 dex, and log Q = −13.5. The profiles were computed assuming v_mic(NLTE) = 5 km s⁻¹ (black), 10 km s⁻¹ (blue) and 15 km s⁻¹ (red). All profiles have been degraded to the resolving power of the VFTS Medusa spectra (R ~ 8000) and convolved with a rotational profile corresponding to v sin i = 100 km s⁻¹. In order to isolate statistical equilibrium effects, a fixed value of v_mic = 5 km s⁻¹ for the formal integral was used in these examples.