If you are plugged in most of the time, the answer is yes, no problem.
The only time the smaller gauge wire/longer run will limit voltage (due to resistance) is at higher charging amps.
Now, if you do a lot of dry camping where you are paying fuel to run a generator and desire a quick charge for deeply discharged batteries, absolutely, consider larger gauge wire. Another option is to ADD another wire to "supplement" the smaller than desired wire.
This is pretty easy to verify: With batteries discharged (below 12.2 VDC which is 50%) plug in/start the generator. You should be at maximum charge amps. Check voltage at the converter and compare to that at the batteries. This will give you the maximum difference. As batteries charge, you will notice that the voltage at batteries more closely matches voltage at the converter.
