I've been diagnosed for over a year. (But suffered for many.) I'm fairly early in developing symptoms, i.e. still very mobile. I've discovered that the triggers for cramps are dehydration and cold. I control these with water, magnesium, calcium, potassium, and heat. No problem. The only trigger I've noticed for trembling, and with a small correlation, is lack of sleep.
So today. Plenty of sleep, (for once,) seems like a good day. Walking through the grocery store, trembling jumps from 0 to like 5/10. Has this happened to you? Thoughts on triggers?

Stress, either physical or mental is a trigger for myself.

I have found that sodium is a trigger for cramps. Eating a high-sodium food is certain to bring them on.

In addition to the ones you mentioned, magnesium citrate is worth considering to avoid cramps.

Haven't had any trouble at the supermarket -- that's a new one! (lol)

Sodium causing cramps might indicate a potassium deficiency.

I find not enough sodium causes my cramps. It's important to keep a journal to figure out all the variables.