A Czochralski process (“CZ”) crystal growth method and furnace having a heater capable of generating a heating zone, a crucible within the heating zone and capable of retaining a volume of molten crystal growth material forming a melt line oriented in a designated position within the heating zone, a seed growth rod retractable from the crucible with a rod retraction mechanism, for forming a crystal boule thereon proximal the melt line from the molten crystal growth material. The furnace causes relative movement between the crucible and heating zone as the crystal boule is retracted, so that the melt line is maintained in the designated position within the heating zone. In some embodiments relative movement is based at least in part on sensed weight of the growing crystal boule. In other embodiments the crucible growth rod retraction mechanism are fixed relative to each other by a gantry.