For my zinc and potassium balance, it is pretty simple. I know that I'm low in zinc when my skin breaks out on the left side, and in potassium when I break out on the right. I have a similar reaction on each side to low levels of calcium and copper, respectively. I also can tell by changes in my visual acuity if my zinc(left-side), calcium(l-side) or potassium(right-side) is low. Like you, I use my stool consistency for a lot of feedback. I know if my magnesium is getting too high or my calcium/potassium isn't high enough to balance it. I'm in the process of lowering all of my supplements after many months of higher doses to treat a very long malabsorption condition. I'm amazed that my body is holding steady at the lower doses without major breakouts or vision reduction. I have had a couple patches of dryness on my face, but my body seems to be retaining the balance very well.