DESPOTIC results for a model with σ_turb = 3 km s⁻¹, 𝒳; = 𝒳;0, ζ = 10⁻¹⁶ s⁻¹ and solar dust abundance. Top panels, from left to right: predicted H₂ column density, Hi column density, H₂ and Hi abundances per H nucleus. Bottom panels, from left to right: Gas temperature, CO abundance per H nucleus, integrated brightness temperature and CO-to-H₂ conversion factor for the ¹²CO(2→1) emission line. Blank pixels denote regions of the grid where the models did not converge. The black contours on the X_CO plot represent an example of the constraint on the parameter space given by our data for MW-C1. Similar radiative-transfer models are used to calculate fiducial conversion factors within each Hi cloud.