That's an excellent formulation, but it's a lot of Mg per day. I'd take one a day until you're out of them, and add an equally good calcium formulation at the same time. If you're still twitching after a week, you might up the dosage to see if it helps. If not, I'd go back to one a day. The next blood panel you get done, you might ask the doctor to include blood electrolyte and mineral levels.

Any more minerals than your body can utilize risks developing kidney stones. My manager actually passed out in work from the pain of kidney stones. He had to have emergency surgery because the stones didn't break up with the new ultrasound blast treatment.

15 minutes in the sun without sunscreen will allow your body to synthesize all the vitamin D you need unless you have very dark skin. If your daily multivitamin has 400 iu, that's all you need.