Hi Active as this ground rod is considered a supplementary ground rod many of the regular requirements do not apply.
250.54 Supplementary Grounding Electrodes.
Supplementary grounding electrodes shall be permitted to be connected to the equipment grounding conductors specified in 250.118 and shall not be required to comply with the electrode bonding requirements of 250.50 or 250.53(C) or the resistance requirements of 250.56, but the earth shall not be used as the sole equipment grounding conductor.
In short if you choose to install this supplementary electrode you simply connect it to the EGC wherever you want with whatever size wire you want.
Unless there is local amendment I do not see how your inspectors could fail this.
Bob
