We chose cutoffs to flag molecule pairs displaying parameterization differences (flagged "different") and pairs displaying no parameterization differences (flagged "similar"). TFD values below 0.20 are believed to be pharmacologically similar , so we chose a TFD value greater than 0.20 to label molecule pairs as different. After visual inspection of a variety of molecules, we observed that molecule pairs with a TanimotoCombo under 0.5 typically had changes due to single bond rotations. Because such bond rotations can arise from a variety of reasons aside from substantial differences in parameterization, we did not wish to focus on such cases. Thus, molecule pairs with a TFD value greater than 0.20 as well as a TanimotoCombo value greater than 0.50 were flagged as different -allowing us to focus on cases with substantial torsional differences which were NOT simply due to rotations around highly flexible bonds. We used a substantial amount of manual inspection of these thresholds to help us make these choices. As a result of these choices, any pair of molecules with a TFD value of 0.18 or less was assigned a similarity flag, as it will display geometrically similar structures. We left a small buffer region between 0.18 and 0.2 when defining similarity flags in order to avoid an extreme sensitivity to small changes around the 0.20 cutoff. Here, we show an example of a molecule pair that we did not deem informative for force field parameterization. The lightly colored molecule was minimized with GAFF, while the darker molecule was minimized with SMIRNOFF. The two minimized structures display little geometric differences outside of the placement of substituents around the sulfonamide group; most of the geometric difference appears due to rotation of a single torsion. The low TFD value of 0.046 implies that these structures are highly similar by TFD, while the low TanimotoCombo value of 0.27 implies that these structures are starkly different by TanimotoCombo. By visual inspection of this molecule and others, we determined that molecule pairs with low Tanimoto Combo and low TFD scores were often not as informative, at least with respect to our goals in this project.