tastethealex
Bluelighter
Or 20mg up-front with the option of topping up another 10mg later on. If you're happy with the effects of 20mg then you've got 10mg left over for another day (which you could always snort to amplify the effects, should you wish).
I had gone back an edited my post, although I completely agree with your statement. They seem pretty set on taking the entire 30mg that night, and so I brought up my opinion on how I felt it should be handled if they do in fact insist on taking all of it.
