Apparently, the composition fluctuations of the co-networks of Figure exceed the stochastic composition fluctuations of the perfectly mixed co-networks in the simulations, even though kinetics did not indicate a large discrepancy. This can be judged from the comparatively large sol fractions (see Table ) in the experiments, see Figure in the SI for data around 𝑐 * and Ref. for simulation data at different concentrations (note the different definition of 𝑐 * ). The reason for this difference is not clear at the moment and will be explored by additional computer simulations.