Great overview.
You also vindicated our cow's hard work making all those psylocybin grow boxes here in Florida! My father used to thoroughly enjoy catching harvesters and asking them why they liked to play in cow manure. He of course knew why but the answers were hilarious.
More seriously, I'm bothered by terms like "spiritually significant" and "mystical experience"! No question these agents will alter your perception of input coming from your senses and will cause you to think differently from that point forward (and to review past thought processes).
But what is a "spirutal significant" event? Is it in opposition to a "spiritually insignificant" event? What is simply "spiriit"? Is it feelings for my football team? A creature with no physical body? A mood that sweeps over my nation? Or even God entering into whatever I am or me entering into whatever God is?
Our notions of "spiritual" are heavily dependent on our culture and socio-economic backgrounds.
I'm begging for some definitions; or minimally some constraints!