hi cece, by and large yes, with a few comments:
1. coffee and tea deserve mention, not just alcohol. diuretic foods and drinks increase magnesium excretion too. it's not just the phosphates, it's the caffeine if memory serves me correctly.
2. i am not keen on the recommended cal:mag ratio. 2 calcium to 1 magnesium is status quo, but if you have issues with spasticity you'd be better off with a 1:1 ratio. in some cases even a 1 calcium to 2 magnesium ratio could be in order.
3. as to form, i use citrate if i want to take magnesium before bed. i take glycinate before meals to get it pushed down into the lower intestine. i used to take magnesium glycinate at bed time but i had a horrific acid reflux cough as a side effect. (moral of the story: do not soak your LES in nutritional muscle relaxants).
as for sou's pill breakdown:
magnesium oxide contains the highest ratio of elemental magnesium compared to other forms. but, it is the least soluble form, difficult to absorb, and because of that it is the most likely to give you the runs.
if you took two of those 400mg pills each with 350mg mag oxide, you might want to stay near the bathroom in case of unexpected surprises :S
with magnesium glycinate you can take higher doses and still have a normal day. best bet recommendations are up to 1200 mg elemental magnesium per day!! i find that hard to achieve. optimal daily intake proposed in literature = 10mg per kg body weight.
hope that helps!
READ ME key info on nutrient targets - www.thisisms.com/ftopict-2489.html
my approach: no meds so far - just nutrient-dense anti-inflammatory whole foods, and supplements where needed
info: www.whfoods.com, www.nutritiondata.com