Evolution of M₁ = 32 M_⊙ and q = 0.85 example binaries with different P_ZAMS, as a function of time till carbon depletion. The top panel shows the mass evolution for the primary and secondary, while the bottom panel shows the period evolution. Similar to the model in Figure 1, the mass transfer starts with a rapid phase, which shrinks the orbit, causing the dips in the period evolutions. However, the mass ratio flips, and the orbit widens again. In general, a tighter initial orbit leads to a shorter period and a more massive companion at carbon depletion, while the helium core mass is independent of P_ZAMS. The STAR+BH conditions of these binaries are marked with a star in Figure 5.