I don’t think you multiplied quite right. An 80-kg person would need 400mg, which would take 40g of shrooms if potency is 10mg per dried gram.
That would still be 10 times larger than a regular dose. I think that would make most people seriously ill, not to mention the mental effects. One must assume that mice respond differently than humans.
It's 5 mg/kg (or 15 mg/kg due to faster metabolism) for rats, and 25 mg (not per kg!) for humans. To be clear, 25 mg is a completely normal dosage that has been used in previous human studies.
That would still be 10 times larger than a regular dose. I think that would make most people seriously ill, not to mention the mental effects. One must assume that mice respond differently than humans.