I'm not an expert on this, but my gut feeling (ha ha) is that it's better to take NC every day (well, I take mine at night). I know for sure that too much magnesium makes my belly rumble and gives me diarrhea. I made that mistake last week because I got some different calcium supplements that have lots of mag added, and then after I started having trouble, I figured out my new mega-multi vitamin had lots of mag. So it was too much.
Take a small amount like a tsp every day, and then increase it by 1/2 tsp if you're getting C. Anyway, that's my take on it.