I'll trust psychonautwiki over your random speculation. Not to be mean, but I would like to add that if you're not familiar with it you probably don't have that much authority on the subject.
I agree on the matter of authority... but if you read the link, it largely suports what garyisabusyguy said. The link says:
the most commonly used mushroom is Psilocybe cubensis, which contains 10–12 mg of psilocybin per gram of dried mushrooms
Which is exactly what garyisabusyguy said.
It also says:
For example, if you want to consume 15 mg psilocybin (a common dose) from cubensis with 1% psilocybin content:
15 mg / 1% = 15/0.01 = 1500 mg = 1.5 g
But it also says that "strong" and "heavy" doses are 2.5-5g (25-60 mg psilocybin) and 5+g (50-60+ mg psilocybin). There's also a bit of inconsistency on the site, because if you look at the page devoted to Psilycybe cubensis, it gives different, slighly larger numbers. It says a common dose is 1-3g, a strong dose is 3-6g and a heavy dose is 6+g.
That all accords pretty will with what garyisabusyguy said, assuming his experience is with people who take doses at the high end of common and greater.
Of course, his ranges still suggest a maximum dose of ~84mg. A typical lab mouse weighs about 30 g = 0.03 kg, so they're taking a dose of 15 mg / .03 kg = 500 mg of psilocybin per kg of body weight. If an 80 kg human takes an 84mg dose, that's 1.05 mg of psilocybin per kg of body weight. So the mice are getting 475 times what appears to be a quite heavy dose for humans.
Further, the LD50 (dosage that is lethal 50% of the time) of psilocybin is 280 mg/kg of body weight. So the mice in the experiment got nearly twice what is usually considered a lethal dose in humans. It's unclear to me how or whether this can apply to humans.
