I would use the 470R for the R and two of them in series for the 2R.
That's going to run into issues with the non-zero output impedance of Arduino pins (datasheet suggests this is of order of 40ohms), and also the unknown impedance variation between pins. Certainly there's no way 12 bit precision can be achieved unless the output impedance is less than 0.1ohm!!
I'd suggest using the 10k resistors instead - if there's enough for about 10 bits that's more precision than can be achieved anyway and at least 10k is going to dwarf the Arduino output pin impedance.