I know what you mean about the Ancient Minerals mag oil. Pretty unpleasant. Tried it, didn't like it, so I tried a different mag oil, one I got from Sunfood.
Way better for long term use. Over a 3 month period of steady use it got rid of my heart palpitations and muscle twitching. Plus, no irritation! I've kept using it every day for over a year and my heart palpitations are still gone.