Our results show that this approach can handle molecular crystals where all the internal degrees of freedom of a given Cartesian block are explicitly modeled. As such, it is a representative example of how Cartesian blocks can be treated in larger molecules. We, therefore, believe that the current work is a useful stepping stone towards assessing the applicability of PGM-based free energy methods to complex and realistic crystal systems, including molecular crystals with multiple conformational degrees of freedom. Across all tests performed in this work, we note how the extrapolation to the thermodynamic limit of an infinitely large cell shows a convincingly convergent behavior enabling a quantitative removal of finite-size effects from both lattice-free energy differences and entropies. The order of magnitude of the uncertainty is particularly important in these estimates. Our current setup showed that a PGM-based approach such as model H enables matching the ground-truth error levels.