Distributions of gold weight per tomographic bin for our fiducial SKiLLS simulations. Individual lines show the scatter in the gold-weight PDFs under different realisations of our spectroscopic calibration samples. The tomographic bins show qualitatively similar behaviour: many sources are consistently classed as gold under all realisations of the SOM (w_gold = 1), and very few sources are consistently classed as not-gold under all realisations (w_gold = 0).