Resolution tests show average inclination as function of time, for different particle sizes (see plot legend), for three of our models (top panel: low-excitation disc using $Q_{\text{D}}^{*}$ model 1; middle panel: low-excitation disc using $Q_{\text{D}}^{*}$ model 3; bottom panel: high-excitation disc using $Q_{\text{D}}^{*}$ model 3) for three different grid resolutions (solid lines: n_e = n_i = 5; dashed lines: n_e = n_i = 10; dotted lines: n_e = n_i = 20). Horizontal blue lines show the lowest grid bin values, i.e. the lowest values to which the average inclination can be damped in each model.