Normalized surface brightness of scattered light at 1.6 μm as a function of radius 10 Myr after particle release for a grid of dynamical dust models with varying gas disc parameters. The panels on the left-hand side are for the mean molecular weight of μ=2.3 and those on the right-hand side are for μ=28. From top to bottom, the radial width of the Gaussian radial profile of the gas disc is varied from 10 au to 25 au. The different colours show different gas densities at the radius of 65 au, as indicated in the plot legends. Collisions are not accounted for in these models and the size distribution exponent is fixed to q=3.5. The grey bands show the approximate locations of the observed rings we aim to match. For details, see Section 4.4.