Comparison of radial velocities (v_r) estimated using the methods in this paper with results from Sana et al. (2013), in which Δv = v_r − v_Sana, and the plotted uncertainties are the standard deviations of both estimates added in quadrature. The upper panel shows the Δv results in the sequence of VFTS identifiers (i.e. increasing right ascension), while the lower panel shows Δv as a function of v_esini.