Two optimization approaches are proposed to en- hance the performance of personal sound zone (PSZ) systems with crosstalk cancellation (XTC). The two approaches adjust the trade-off between two important performance attributes of a system: acoustic isolation and crosstalk cancellation, by either modifying the cost function in the optimization problem (the direct approach) or controlling the amount of crosstalk in the target transfer functions (the indirect approach) in the filter generation process. The effectiveness of the two approaches is evaluated using metrics of inter-program isolation (IPI) and XTC level, through numerical simulations based on both a free-field system model and actual transfer function measurements. The results show that at low frequencies, the two approaches can effectively control the trade-off between the two attributes, but their effectiveness is reduced at high frequencies due to the small wavelength. Furthermore, the results demonstrate that the direct approach is more effective in manipulating the trade-off, whereas the indirect approach provides more precise control over the desired XTC performance.