Spin hyperparameter posteriors of the COMPACTNESS PEAKS model, where μ_χ is the mean of the spin magnitude distribution, σ_χ is the width of the spin magnitude distribution, ζ is the fraction of BBHs in the subpopulation aligned with respect to the orbital angular momentum and σ_t is the width of the spin orientation distribution for the subpopulation aligned with respect to the orbital angular momentum for a given component. Left panel: The spin parameters paired with the BH_L and BH_H peaks Right panel: The spin parameters paired with the powerlaw (PL) component. The credible intervals on the 2D posterior distributions are at 1σ, 2σ and 3σ, using increasingly light shading. The intervals on the 1D posterior distributions are at 1σ.