I strongly suggest that everyone stick to the suggested 100mg to 350mg dosage range suggested by the author.

Some forums and health websites suggest significantly higher doses, but I think that's a bad idea. Your body will tightly regulate magnesium levels within a specific range. Large doses (500mg+ per day) will just make your body work harder to eliminate the extra magnesium.

Also consider that Gwern famously self-experimented with magnesium on two separate occasions, and found a long-term trend toward decreased performance: https://www.gwern.net/nootropics/Magnesium It's anecdotal, of course, but it's not hard to imagine that the megadoses of magnesium could cause electrolyte imbalances or other disturbances if continued long term.

Keep it low dose and keep it safe.