In the following sections, benchmarks are presented to evaluate the performance of directly using the activation energies of model reactions to approximate larger reactions involving both closedshell and open-shell organic chemistries. For scenarios where the model reactions are used as a starting point for localizing transition states of larger reactions, a benchmark is performed to evaluate the performance of four sampling schemes in predicting the activation energies of various reactions. We conclude with a benchmark case study for alkane pyrolysis that illustrates the power of the model reaction concept in simplifying larger reaction spaces. Mean signed errors (MSEs)