(a) Contour plot of DTW path lengths with a varying magnitude of the V_max and V_min terms for the tomography-derived inner boundary condition. The minimum DTW path distance is marked by a white cross, and this point gives the optimal values of V_max and V_min of 480 and 220 km s⁻¹, respectively. (b) DTW path lengths as a function of varying scale parameters for the MAS-derived inner boundary condition with the white cross showing the optimum VM_min and VM_max parameters of 280 and 580 km s⁻¹ respectively.