In this study, we aim to rigorously assess whether it is more beneficial to train the intermolecular LJ parameters of a force field on solely pure substance data, binary mixture data, or a combination of both, with an emphasis here on density-related properties ( , ( )) and enthalpic properties (Δ , Δ ( )). A combination of density and enthalpic data should be generally sufficient to constrain the LJ and parameters, with densities providing the most information about and enthalpic properties providing information on via the cohesive forces between molecules, though there is of course some partial cross-correlation between parameters .