where does the code address the order of calculating condudtor size if voltage drop, ambient temp. and conduit fill are all factors to consider? Depending on which you figure first, your answer will vary considerably.
The voltage drop calculation is independent of the adjustment factors for more that 3 current carrying conductors and ambient temperature. Apply the two adjustment factors to the circuit ampacity to determine the minimum conductor size. If this size results in too high of a voltage drop, then just increase the minimum required conductor size for the desired voltage drop.