Figures , and 14 show the deviations in partial charges between explicit AM1-BCC-ELF10 and monomer-averaged RCT charges for smaller chains generated with the aid of MoSDef's mbuild molecule builder. RCT charges do not deviate far from explicit AM1-BCC-ELF10 charges, as these RCT charges must be used as proxies for AM1-BCC-ELF10 for longer polymers. As pointed out in the "Charge Assignment" section, the AM1-BCC-ELF10 charging method used as a "ground truth" for partial charges scales poorly to systems with hundreds of atoms whereas the application of library charges scales with the same Apart from a handful of outlier atoms, the exact and the RCT-averaged library charges are very nearly the same, with outliers occurring due to changing chemical environments at chain ends and due to steric overlap from conformer AM1-BCC-ELF10 conformer sampling for middle monomers. The differences between AM1-BCC-ELF10 exact and RCT charges are unimodally distributed and tightly centered around 0.0 e with RMSE values not exceeding 0.010 elementary charge for all three molecules and with outliers never exceeding 0.04 esu difference. Such differences are highly unlikely to affect physical property estimation outside of statistical noise, and have the additional benefit of being independent of the configurations of longer polymer chains. Bearing these differences in mind and acknowledging the slight deviations from AM1-BCC, We will use RCT charges as a proxy for AM1-BCC-ELF10 charges when assessing GNN charges for large systems in ensuing discussion, as AM1-BCC-ELF10 charges simply cannot be generated for arbitrarily large molecules.