before any comparison against theoretical or observational constraints [@ThornburyEtAl2014; @DruryEtAl2017].

Finally, convection also arises quite naturally in the framework discussed above. We include convection in the standard way by means of the convection velocity \[eq:vc\] \_[c]{}(z) = V\_[c]{}\_z, where $z$ is the vertical coordinate and $\vec{e}_z$ the unit vector along the vertical axis crossing the magnetic slab of extension $[-L,L]$ along that axis.

Benchmark models {#ssec:benchmarks}
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In the most general case, the free parameters featuring the propagation modeling that we have introduced above are the following: $L$ for the magnetic halo size; $K_{10}$, $\delta$, $\eta$, $R_{\rm l}$, $\delta_{\rm l}$ (equivalently $\Delta_{\rm l}$), $s_{\rm l}$, $R_{\rm h}$, $\Delta_{\rm h}$ (equivalently $\delta_{\rm h}$), and $s_{\rm h}$ for the diffusion coefficient; $V_{\rm A}$ for reacceleration; $V_{\rm c}$ for convection. This is a 12-parameter space, hence a huge configuration volume to explore.

Based on previous studies, we can further fix $L$ which is highly correlated with $K_{10}$, see discussion in . Unless specified otherwise, we will set $L$ to 10 kpc in the following. Moreover, as anticipated in , the determination of (an interval for) the three parameters describing the high-rigidity break benefits from fits including primary species, see . Finally, without loss 