Comparison of the final [Mg/Fe] stellar dispersion of the Fornax and Sextans (r= 6) models run with different schemes. As in Fig. 10 and 11, black curves show the 1σ dispersion around the mean and is also reported in the third section of each panel. The comparison of the metallicity distribution function is shown on the bottom of each panel. For comparison, observations at low metallicity ([ Mg / Fe ] < −2.5) of individual stars taken from Fig. 1, are shown in yellow. In the [Mg/Fe] vs [Fe/H] plot, the shaded region corresponds to the 1σ dispersion around the mean. Individual measurements are shown with small stars. Panels a) and e) show the effect of the smooth metallicity scheme on Fornax and Sextans. The model run with elements spreading independent of the distance to the source (w_ij = Γ_ij) is indicated on panel b). The effect of imposing a constant ejection radius (R_ej = 0.125 kpc) or fixing it to the blast radius (R_ej = R_E) are shown on panels c) and d) respectively. The diffusion effect is dhown on panels f) to h). In those latter plots, the dispersion is compared to the fiducial model run with the smooth metallicity scheme, corresponding to the top of panel a).