Potassium nitrate yields 66% nitrates. You can reasonabley and safely use about 1.6g KNO3 to yield about 1g of NO3 when run concurrently with Vit C. I suggest titrating up to that dose as some shortness of breath may happen as you adjust. At that amount you need to find a more cost effective route.

BTW - add 1g of Agmatine and 6-8g of l-citrulline to that and you're performance capacity and intraset recovery is remarkably improved. The libido enhancement via LH stimulating of Agmatine in addition to the VO2 increase via NO3's and l-citrulline make for quite the performance...