Bespoke FF parametrization has the potential to significantly improve the accuracy of binding free energy calculations in drug discovery applications. With increased compute power, resources for data storage and The optimized torsion parameters improve the agreement between our QM reference and MM modelled potential energy surfaces, from 1.1 kcal/mol for the base FF to 0.4 kcal/mol using the default BespokeFit workflow settings. As well as providing a concise base FF, the use of SMIRKS patterns to encode the bespoke torsion terms also means that they are transferable without modification between fragmented molecules and their parents. We have made extensive use of this feature to build bespoke FFs for a congeneric series of inhibitors of TYK2. We find that, while the base Parsley FF (OpenFF 1.3.0) provides competitive accuracy, our BespokeFit FF leads to improvements in all reported free energy statistical measures.