The extratropical circulation response to ENSO Sea Surface Temperature (SST) and related tropical heating anomalies relies on a ‘typical’ maximum divergent outflow level for the calculation of the Rossby Wave Source (RWS) terms. However, the actual level of the maximum divergence and its spatial structure can vary significantly both in models and even among different reanalysis products. These variations can impact the interpretation of the divergent source terms in the RWS, and affect the strength and nature of extratropical teleconnections. We present results from the E3SM and CESM large ensemble sets showing that variations in the circulation response can be traced to different vertical divergent structures and ultimately different profiles of tropical heating. These variations in the mean and anomalous divergent outflow characteristics can impact the nature of the ENSO-forced Rossby wave patterns and can be linked to variations in the vertical heating response to SST. We find that even though the anomalies in divergence may be well represented, the level of maximum anomalous divergence may not be the same as the mean divergent level. This separation can be significant, both regionally and for different ENSO phases. In addition, the variation in diabatic processes within each large ensemble can impact the extratropical variability in distinctly different ways, depending on the choice of large ensemble.