Well... i dont know anything about amounts, but no matter how much you eat, remember that it takes some time until you start to feel the effects (1 hour or so), and they rise slowly and steadily during some 2-3 hours before reaching its peak, and last for several hours... sometimes you can be still pretty baked the day after... so be careful, and plan your trip beforehand.
Also, eating with a full stomach usually doesnt work. Eat it with the stomach as empty as possible.
And the effects are different from smoked weed. Its more of a body stone, when you feel relaxed, heavy and peaceful... but when eaten in high doses it can be even a bit psychedelic... :stoned:
So, enjoy, and good luck! :thumbsup: