dude... i have heard to eat an eighth.
Don't totally follow this because i do not do them.
I think it might also depend on the potency of the mushrooms.
also i have heard that the caps have the hallucinagen,
and that the stems give you the body buzz. Kinda easy to remember.
that is all i know. I picked shrooms from my horse once and gave them to my friend.
He ate 4 and it did nothing to him. I wouldn't consider them too dangerous. about 8 or so caps and stems should get you a steady high.