Properties of the pseudo-isothermal dwarf (top) and NFW dwarf (bottom) in isolation after 6 Gyr of evolution. The properties of the Sextans dSph are shown with a red dashed line in the [Fe/H] histogram (middle panel) (Battaglia et al. 2011). The [Mg/Fe] v [Fe/H] of available RGB stars (Shetrone et al. 2001; Aoki et al. 2009; Tafelmeyer et al. 2010; Kirby et al. 2011; Theler et al., in prep.), selected as per Theler et al. (in prep.), are shown with points in the third panel. The Mg values are derived from one line and show much larger scatter at low α that is not observed (see Theler et al., in prep.). The median [Mg/Fe] in each [Fe/H] bin of the stellar particles is shown with a cyan line in the same panel. This choice of parameters achieves the approximate metallicity distribution (although missing the most metal rich stars) and the turnover in [α/Fe] of Sextans dSph.