We show that the mesoscopic incommensurate $mathbb{Z}_2$ vortex crystals proposed for layered triangular anisotropic magnets can be most saliently identified by two distinctive signatures in dynamical spin response experiments: The presence of pseudo-Goldstone `phonon modes at low frequencies $omega$, associated with the collective vibrations of the vortex cores, and a characteristic multi-scattered intensity profile at higher $omega$, arising from a large number of Bragg reflections and magnon bandgaps. These are direct fingerprints of the large vortex sizes and magnetic unit cells and the solitonic spin profile around the vortex cores.
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