In the direct MaxFlux method, the energy evaluation points are not updated, and the equal spacing is maintained. As described in Section 2.3, the optimization is repeated five times with a stepwise update of β. We have added FB-ENM as an ASE Calculator class to our Python implementation of the direct MaxFlux method and have also implemented a routine that automatically performs the above optimization, requiring only the structures of the reactant and product as inputs. The results in this section were calculated using this routine. In this routine, one of the convergence criteria of IPOPT, dual inf tol, is relaxed to 0.1. Preliminary calculations confirm that this is sufficient when using FB-ENM (not shown).