Left-hand panel: variation of the three mass parameters of the three MN-disk models as a function of the disk thickness ratio b/R_d, for the modelling of the thin stellar disk. Right-hand panel: variation of the three scale-length parameters as a function of the ratio b/R_d. In the panels, the points represent the optimal solutions found after the application of the cross-entropy algorithm. Solid lines are fourth-order polynomial fits to the distribution of points.