These data are shown in Figure for an equimolar monomer ratio with an initial monomer concentration of 200 mM in dichloromethane using Grubbs third generation bis-pyridyl complex as the initiator. Visually, the model fits the data well and captures the halting of the reaction at near quantitative endo-NB conversion without complete iPrSi8 consumption, which is a hallmark of equilibrium (co)polymerization. The best-fit parameters for this system are listed in Table (with values of uncertainty determined through bootstrapping methods, see Supporting