Due to the immense computational burden (having to train O(N 2 ) models where N is the number of molecules in the withheld set), we only performed this analysis on one particular split of the "Largest Cluster" data. The results are shown in Figure . We show that for this fold there does exist an optimal ordering of withheld set molecules that results in a smaller subset of molecules that can achieve the same final performance as adding all of the withheld molecules to the training set. Interestingly, we also show that maximal model performance can be achieved by intentionally not adding all of the withheld molecules, which