KERRBB (solid orange line) and SLIMBH (solid blue line) sets of M and λ values consistent with 1508+5714 data. The two sets of results are compared with the virial mass (vertical red line), in order to estimate the respective values of the Eddington ratio ${\lambda }_{\mathrm{vir}}^s$ (dashed blue and orange lines for KERRBB and SLIMBH, respectively). The vertical and horizontal dashed gray lines show the estimates of M and λ derived with SS73, respectively.