If you want to optimize for accuracy, have a look at Palladian’s “Threshold Analyzer” node:
It’ll draw a plot of Precision, Recall, F1 and Accuracy (though Accuracy is currently not mentioned in the docs – note to myself) for an interval of thresholds from 0 … 1. Beside that, it’ll give you an output table with all the values from the graph – you can use this to find the optimal threshold.