Integrated thermal timescale t_th,int (red dashed) and front propagation timescale t_fp (blue solid) as a function of black hole mass, computed for λ_Edd = 0.01, R = 20 R_Schw, and α_B = 0.5. The shaded band marks typical observed CLAGN transition durations. The annotation in the upper left indicates the qualitative dependence of t_fp on the model parameters held fixed in this figure.