Let me throw this out... how about starting with 2.0 and finishing off the 1.5 at maybe t + 3 hours or so.

I ask because I personally don't get much from later hits of grass. Is it the same with shrooms? would it be a waste to use the remaining 1.5 to boost with? would I be too exhausted to extend the trip?
(Hope you don't mind me going this way in with this thread, Canabliss)