This has been asked on some of the other forums as well and I haven't seen a good answer. There have also been some people who said the physically undesirable parts were more intense than with San Pedro/Peruvian Torch. If I had to I would guess maybe 80-100grams dried. It doesn't contain as many actives as the more traditionally used cacti.
I have tried it..my and my boyfriends trip report is on Erowid. It was thoroughly unpleasant...the body load and sickness was incredible and I felt like I had been poisoned. http://www.erowid.org/experiences/exp.php?ID=35075
if you are taking the dried outer flesh chips, then the dosage should be around 35-40g's the firsttime. As it is reported that the dried outer flesh is more potent than whiole cactus gram by gram.