Zoom-in on the three mass transfer phases of the ULX model at metallicity log Z = −3.0 shown in Fig. 7, including simulations where the Eddington limit was increased by factors of 3 and 10. Dashed and dotted lines show the estimated luminosity that simulations with increased Eddington factors would have, using the potential luminosity a source could reach in the simulation strictly limited to the Eddington rate. Top: Mass transfer efficiency. Middle: Orbital periods. Bottom: Accretion luminosity.