There used to be a "tolerance" parameter as an alternative stopping criterion to number of iterations - this seems to have disappeared from the ShapeWorksTools. In the old NoGuiCorrespondence application, there's a line at the very end of InitializeSampler():
m_Sampler->GetOptimizer()->SetTolerance(m_tolerance) ; 

with m_tolerance being a value read from the parameter file. Could we bring option this back?