Well... I must say that last evening was an amazing san pedro experience.
I bought 3 12" clippings, boiled them all over a low simmer for about 8 hours, drained through cheese cloth, and proceeded to drink down about three 8 oz glass over the course of an hour. This time, I made sure to keep it at a very low simmer just bordering on a sliight boil.
I started to feel tingles after about an hour, but it wasn't until 2+ hours that it stated to come on strongly. It lasted most of the night!

It was more of a body high than a head fuck, but my thinking was most definitively scattered, as it still is 18 hours later. there were lots of Phen visuals with enhanced colors, trails, and blurred/double vision. I was feeling more overstimulated than I was comfortable with, much like the 2C's do to me, so I ate down a bunch of Xanax to chill out a little. It didn't really blunt the trip, just relaxed me a little more.
My lesson leaned is to ALWAYS boil down all 3 12" clippings if you want more intense effects. No moer just boiling down just 18" thinking that should be enough. I can always stop drinking once it is prepared instead of starting a whole new cook once I run out
Well... just thought I'd pass along my experience in case it can be of hep to others. Always prepare more than what you think you'll need so you can still drink more if you're not where you want to be.