This work compares simulations of intrinsic point defect transport for a 0.8 " crystal for two different values of the point defect recombination factor, thereafter utilizing the model for two more commercially relevant 4 " crystals, grown with the needle-eye technique. Using this approach to study defect transport in floating-zone configurations is the novelty of this work. The simulation of the thin 0.8 " crystal is compared to the qualitative Voronkov model and DLTS experiments, to give some insights on the applied recombination factors. The work concludes that for large crystals, grown in the vacancy region, the influence of an uncertain recombination factor is not as significant as for smaller crystals grown with a near critical growth parameter.