a coarse-grained approach*

We report a comprehensive neutron scattering study of low energy magnetic excitations in the breathing pyrochlore helimagnetic Cu₂OSeO₃. Fully documenting the four lowest energy modes that leave the ferrimagnetic configuration of the "strong tetrahedra" intact (\hbar ω<13 meV), we find quadratic dispersion at the Γ point for energies above 0.2 meV with any gap less than 0.19 meV, two doublets separated by 1.6(2) meV at the R point, and a bounded continuum at the X point. Our constrained rigid spin cluster model relates these features to Dzyaloshinskii-Moriya(DM) interactions and the incommensurate helical ground state. Combining conventional spin wave theory with a spin cluster form-factor accurately reproduces the measured equal time structure factor through multiple Brillouin zones. An effective spin Hamiltonian describing the complex anisotropic inter-cluster interactions is obtained.