Your mention of calcium/magnesium balance struck a chord with me, so I wanted to see how you were doing with this. I do not have elevated blood levels of Calcium (and can't seem to get my Magnesium checked; the labs claim the test is no longer done), but as we all probably know, the body is excellent at maintaining homeostasis, and will do so at all costs...even to our bones. So I realize that normal serum Ca levels might not mean anything. My D3 levels WERE low, though.
That said, I, too, have had some issues with Ca & Mg balance, which I can discern by my symptoms. For a while I was taking a supplement with 250mg Ca to 50mg Mg ratio, as well as 2000 IU of D3 per day. This worked for a while, but now I find that, since I eat about 3 ounces of cheese per day (in addition to all the minerals I get from my veggies), I no longer need the Ca supplement (still taking D3 though, and it has raised my levels into normal range), as supplementing causes cramps, backache, muscle spasms and twitches. Unfortunately, supplementing ONLY with Mg, even in small doses (I've tried Mg Glycinate and Citrate), seems to trigger and/or worsen my diarrhea. I'm doing low-carb, so I can't consume many foods (such as all-bran) that contain Mg. Cashews & almonds are the best sources I've found that I'm allowed, but I'm rarely hungry enough to eat them. The only way I can seem to get any Mg without either triggering intestinal issues or overeating horribly, is by soaking with Epsom Salts , but I can't get quite enough via that method to stop all cramps and twitches.
That is what my personal Ca/Mg balance problems/solutions consist of. I'd love to hear about yours (and anyone else's, if they've noticed it)!