Cramping tends to be more cal/mag related than potassium. Potassium helps with muscle fatigue. A whole teaspoon of NuSalt is too much. 1/8th of a teaspoon will give you 500+mg of potassium, more than enough. When ever supplementing with potassium make sure you are well hydrated.

Calcium RDA is between 1000-1500 depending on age/sex. Magnesium is 400-600 also age/sex dependant. Getting both together in one pill is usually easier. Ratio is usually 2:1 (333mg cal/167 mg mag). Be sure you minerals are chelated (or citrate). You do not want calcium carbonate from oyster shells - it's very hard to digest.

HTH
Nat