I'm researching. Magnesium and am finding conflicting info, any help is appreciated. How am I supposed to tell the diff and how much of each?

Magnesium Chelate- told must be chelate
Magnesium glycinate- supposed to be good
Magnesium Malate (contains Malic acid that's supposed to help too)
Magnesium Citrate - supposed to be good
Magnesium Oxide- (some say it doesn't work as well and can give you diarrhea)
Magnesium Oil - good to rub on skin to bypass stomach and any bowel problems
Magnesium Chloride - in the oil, is this good?