If I were running a continuous WC system I wouldnt dose. I would find a salt that has proper levels of alk/calc/mag and let the salt replenish them. I think as long as you mix the salt to the same salinity as the tank you could only benefit from this method. if its 10gallons, I think 1 gallon a day would work to reduce nutrients and supply additives but if not just increase it until it reaches the equilibrium point.
Please note- I have no experience with this method and my statements are only educated guesses from my experiences.