McKenna also said the best way to enjoy cannabis was once every few weeks in a very heavy single dose.
I guess that's just McKenna for you, I love the guy a lot and quote him often, but some of his ideas were just opinionated in his own way.
McKenna was a hardcore psychonaut. I think cannabis is best used in lower dosages to enchance life, experiences or other drugs.
Don't get me wrong, I would eat acid every day for breakfast if I could and I tend to push the limits when it comes to psychedelics/drugs... Cannabis does have a huge potential as a psychedelic, but if fucks with your GABA system too much IMO.
I think cannabis has the most potential as medicine/enhancer rather than a psychedelic. In higher doses it mimics a psychosis too much. Just my opinion, though.