Spicoli might be right. I tripped with some friends last thursday on shrooms. three of us took 2 grams and our asses were kicked just right (i'm a male 160 pounds). The woman in our group took a gram and did not trip nearly as hard (maybe 120 pounds). So I guess you might consider rock-paper-scissoring for the two grams. (go Scissor-Scissor-Rock and your buddy will be wishing you'd never convinced him to split it up)

But then again tripping is better with more people. tough call