All my NVA artillery is in the Tay Nhin area on the Ho Chi Min trail. He makes taking out my artillery a high priority, so I don't really try to get at him with it, except for special occasions. Losses have been too high recently though.
OK, this is bad. Keep the NVN artillery in NVN, back from the border, with an NVN Regiment and a VC Regiment in the stack to absorb blows from counter bombardment. Use the artillery to bombard ARVN garrisons, and to fire in support of your VC lining the border. See how he likes large firepower coming back .
There is a great little Town just inside the border, Con Thien. Holding it is a nightmare for the FWA, and losing it is a running sore in Quang Tri. Pacification is a misery in Quang Tri
EDIT: Tay Ninh!.. isn't this province at 0 pacification anyway?