Radial profiles of the dust-to-gas scale height ratio at t = 400 T₀ from models with α = 10⁻⁴ (panel a) and α = 10⁻⁵ (panel b), both with St₀ = 10⁻³. The dust scale heights are measured using the root mean square ($H_{\mathrm{d}}^{\mathrm{r}\mathrm{m}\mathrm{s}}$, Eq. (27)), the standard deviation ($H_{\mathrm{d}}^{\mathrm{s}\mathrm{t}\mathrm{d}}$, Eq. (28)), or by fitting a Gaussian profile. The dashed curve indicates a reference-only expected ratio assuming explicit dust diffusion, as given by Eq. (29). The radial extent is the same as in Figs. 1 and 4.