Distribution of the RV RMS associated with 9281 sub-masks of an example run with n_sample = 50 and n_stop = 100. Each RMS value is obtained after a 3σ clipping of the RV data set, which prevents outliers from contaminating the distinction between stable and unstable sub-masks. The RMS values are sorted in ascending order and truncated at 1 km s⁻¹ for visualisation purposes (the maximum can reach up to 100 km s⁻¹). Shown are the 1st (black solid line) and 10th (dashed black line) percentiles of the distribution.