Pair-up times t_pair as a function of SMBH mass in SG AGN disks, for different combinations of the viscosity parameter α (left: 0.01; right: 0.1) and torque prescriptions (top: G24; bottom: B16). Each panel shows a median line and contours enclosing 68% and 90% of the pair-up time distribution, based on our simulations. Results are shown for two different Type II migration prescriptions, indicated by color and line style. In blue, dashed lines: full gap opening, as in the main text (eq. 15). In red, continuous lines: partial gap opening, as in this appendix (K18).