I found about 85 % water when I dried most of mine, some higher some lower. I've never ate as little as 2g wet, but I'd be very surprised with my body size if I felt anything. I'd eaten as little as 1.5g dried and only got light effects. Typically for my size(6'5" 220lbs) I eat between 3-4gs dry(or about 30-35g wet) for a good night, 2g if I just want to feel it and chill.
I usually suggest most people eat about 2g dry (20g wet) to get a nice idea what its all about the first time. I've never gave someone 2g there first time and not had them wanting more the next time.
My favorite method for fresh mushrooms is to chop them up and put them on a cheeseburger.
Also prepare some blunts they are the best when tripping for me!