Sérsic index distribution of galaxies in the COSMOS catalogue from Hernández-Martín et al. (2020), based on Sérsic profile fits provided by GALSIM (Mandelbaum et al. 2012; Rowe et al. 2015). The sharp peak in the final bin results from a Sérsic index limit in GALSIM, where all galaxies with an estimated index greater than 6.2 are grouped. When sampling Sérsic indices for our simulations, we drew from this distribution excluding the final bin. For details on the COSMOS catalogue, see Laigle et al. (2016).