TAS reveals that these conditions coincide with the RubpyC17 -lifetime shortening from 375 to 190 s in However, neither the highest YieldCO and QYCO nor highest TONCO and TOFCO were obtained at the holistic optimum because a compromise in conditions is required (Table ). At conditions for the highest YieldCO and QYCO (7.2±0.04 µmol h -1 and 0.19±0.01%), the TONCO and TOFCO are ~50% Shapley additive explanations (SHAP) were then employed to quantify the importance of each parameter (system component) on the system performance (Fig 5A ), revealing the buffer concentration as the parameter with dominating importance (61%), far more than the catalyst or photosensitiser concentrations (16 and 12%, respectively). While the buffer concentration allows the ionic strength to be varied and thereby provides control of micelle size, its importance is seemingly contradictory to the heuristic optimisation wherein the concentration of buffer did not affect the system until it lowered solubility and hindered performance (Fig ). However, the ubiquitous heuristic optimisation did not consider dependencies between the variables, thereby exemplifying the value of the statistics driven holistic optimisation demonstrated herein. Machine learning regression and the SHAP routine then extracted the importance of each parameter to individual figures of merit (Fig 5B ), thereby providing insight into the conditions that favour high YieldCO and QYCO vs those that favour high TONCO and TOFCO. In all cases the buffer concentration remains the most important factor, with comparably dominating importance to TONCO and TOFCO (64-65%), yet buffer concentration is far less important to YieldCO and QYCO (42-43%) where the catalyst and photosensitiser concentrations grow in importance (27 and 22%, respectively). Thereby, the conflicting requirements to have high YieldCO vs high TOFCO can be quantitatively linked to different parameters. Consistent with these results, maximum CO yield is reached with 4.5-fold higher catalyst concentration than maximum TOFCO (9.8 vs 2.2 µM), whereas higher buffer concentration is required for maximum TOFCO (509 vs 323 mM). The holistically optimised results balance these two requirements, yet a similar photosensitiser concentration is maintained for all three maxima, presumably to maximise light absorption and quantum yield.