Hooray! This has been my go-to solution as well, even at several weeks brooding, sticking fertile eggs under the hen seems like the best 'natural' choice.
Waterboarding" my hens in the past has disturbed me at least as much as it did them. I have tried that "ice bucket challenge" version on a militantly broody hens whom I thought were just a I just became afraid that the drastic lengths these birds were pushing me to might kill them, especially after a couple weeks of just sitting in the nest box making angry dinosaur hisses at every little movement.
Please let us know how it goes!