I have LOTS of experience with MT2! Here are my findings! Remember this largely depends on your skin type.
Anything over about 200mcg causes me to freckle very rapidly. There is a very definite threshold where I start to freckle, even a little over, and I get lots of them, but if I stay under that threshold, I get almost zero new freckles. 150mcg is about that point for me.
I do 150mcg 3x week before going in the sun and I get great results.
I call it "stomach ache in a bottle" as I always get a little nausea at any dose, but it goes away rapidly.
I have tried 150mcg before AND after going in the sun (about 3 hours apart), this leads to rapid freckling.
Awesome, I just realized this thread is from 06, hopefully you are still looking for info lol.