Adapt code to take into account networking details uncovered during earlier benchmark run and test

In #46 (comment 214658), @vsellier notes that so far, loaders seem to be limited by inter-node connection and he lays out a way on how to address it. While he is away, one of us should dig through this and, if necessary, adapt our code to take this into account (make it configurable, though). Then run another larger-scale run to test and monitor it.