If you have wye distribution you will always have stray voltage. It just can't be avoided. The voltage drop in the PoCo neutral is going to show up on the grounding conductors, throughout the system. I have about 3a on my neutral to the PoCo through my GES with the power off. My GES may be the best ground electrode on my street tho. I just try to be sure everything around the house is bonded to my "ground" so I don't have gradients.
You can have all the electrodes you want, as long as they are bonded together with the appropriate conductors. I am a fan of "the more the better". I have 6 rods around the house, 2 "building" Ufers and the King Kong of all Ufers, an in ground concrete pool.
