Some doctors are recommending only a maximum of 600mg of calcium a day, when using high dose D. Vit D greatly increases the amount of calcium absorbed in the intestine.

The magnesium however... should not be oxide form...so check your label of the coral product.

A good product for magnesium is SlowMag, which is affordable now at WalMart. Their website is very helpful in explaining food sources too. One SlowMag twice a day, is the basic dose and suggested for those only getting 1/2 of their mag from food:

http://www.slowmag.com/

This product was originally targeting doctors and pharmacists, back in the late '80's. It was made by Searle, and remains OTC, but now owned by Purdue. Now that the price has come down, and it is commonly sold at WalMart, I tend to recommend it for newbies. But any chelate you want to use will work as well.
Glycinate
taurate
malate
citrate
gluconate
lactate
are some.

There is a very good lotion, now, a reformulated version of CVS epsom lotion, (which was discontinued) 2 yrs ago.
Morton's Epsom lotion is also at WalMart at $5.98 for 8oz. A small dollop rubbed into the skin (if you have muscle pain or foot pain, etc) will provide magnesium that way. It is a very nice elegant product. Non-greasy, no fragrance.

http://www.mortonsalt.com/for-your-h...-epsom-lotion/

A little goes a long way, so don't over use--it is not like a skin moisturizer. We at PN use this and it is great ... just about my favorite thing now!