Distribution of M_*, M_•, sSFR, f_Edd, redshift, and q for the overall population of numerical BH mergers (in blue), for radio-observable mergers (AGN-dominated mergers where F_X, • > F_X, lim, in green) and for EM counterparts (in orange). All histograms are normalised to unity. Observable BH mergers are hosted in more massive galaxies, have lower sSFR and higher f_Edd with respect to the general BH-merging population. All radio-observable mergers are also X-ray-observable.