If your electrolytes are balanced, you shouldn't get cramps. Cramping is caused by not having enough potassium, which is used by your nerves to signal relaxing muscles. Sodium is used to signal clenching. Too much sodium for the potassium and the signals get unbalanced and you can't relax that muscle.

Magnesium and calcium also play a role and deficiencies can result in cramping or tremors (like unsteady hands might just be from being low on Mg, Ca, or K).

So it seems like you've been eating well at least as far as electrolytes are concerned, especially if you can hold your hand out rock steady, regardless of whether your muscles are clenched or relaxed.