Optimisation of the randomised algorithm control variables. The simulation grid for each (n_sample, n_stop) combination is shown, with data points coded by colour and size according to the RV RMS and number of lines within the sub-mask, respectively. The optimised (n_sample, n_stop) pair is (50, 100), ensuring both a precise RV data set and a dense exploration of the sub-mask space. The panels from left to right illustrate the 10th, 5th, and 1st percentile case.