I use Magnesium Bisgylcinate, 200mg. (Bisglycinate is apparently the same as Glycinate, just depends on how close to the scientific name the marketing people went)

Some people take 500mg but I couldn’t find that in Canada. Also, despite selling Magnesium + Calcium supplements, apparently the Calcium competes with the Magnesium for absorption so never take those together.

Any form that is chelated is usually recommended but it also depends on desired outcomes, for example threonate form of magnesium supplements is able to cross the blood brain barrier. I personally use magnesium glycinate at 200mg almost daily.