Relative MBH orbital separation (in units of the initial separation) as a function of time in units of for a binary with initial eccentricity e₀ = 0. Only the first ~2 orbits are shown to highlight the differences in the orbital evolution caused by the different accretion prescriptions. Black solid line refers to the run without any implementation of accretion onto the secondary (the no-accretion model). The red plus line refers to the Bound model and the blue crosses line to the RL model (lowest line). Green diamonds, purple stars, and orange circles refer to the Fix models with sink radii R_fix = 0.5, 0.25, and 0.05, respectively.