Complete fusion cross sections in heavy-ion reactions are studied for various systems in the entrance channel. It is shown that the maximum of the complete fusion cross sections for obtaining low excited transfermium elements corresponds to the same target-projectile combination as suggested by the fragmentation theory. Calculations based on the computer code OVERLAID ALICE show also that the cross sections for light-particle evaporation are maximum for the same target-projectile combination. The calculations are illustrated for the compound nucleus ²⁵²102.