Mode wavenumber, k, and orientation, k_Z/k, for the instabilities found in the regime of Fig. 5. Different instability domains are identified as follows: SMRI_⊥ modes share the growth rates of SMRI_∥ but are oriented nearly radially. As stratification increases, the SMRI branch is stabilised and MGSF modes dominate. These MGSF modes are clearly distinct from SMRI_⊥, exhibiting different growth rates, more horizontal orientation (lower k_Z/k), and smaller spatial scales (larger k).