The average RMSE in the energy profiles and RMSD in the relaxed coordinates, for both the base Sage and bespoke FFs, relative to the QC torsion scans are shown in Table . As expected, the bespoke parametrization shows a clear improvement in the energy profiles across the set of 671 torsion scans, with the average RMSE reducing from 1.1 (base Sage) to 0.4 kcal/mol (Sage+BespokeFit). Figure exemplifies the improvement in the potential energy surface using BespokeFit, compared with the QM reference data and base Sage parametrization. It is important to emphasize that we would not expect the energy error using Bespoke-Fit to reach zero, both because of limitations in the FF functional form, and because the default BespokeFit workflow attenuates the contributions of any reference data with relative energy between 1.0-10.0 kcal/mol above the minimum (see Section 2.6). A further twelve representative torsion scans are shown in Figures , and demonstrate a generally very good agreement between BespokeFit and QM torsion scans at low energies, with some larger deviations in the high energy regions.