[cwkoss]

I think "they all were sober within 24 hours" is too strong of a statement - LSD's half life is 3.6 hours, so after 24 hours blood concentration should be reduced to ~1/64th. Sober within 2-3 days is probably accurate, but I bet anyone who took a 100x dose doesn't feel "normal" for at least a couple weeks, perhaps months - more from PTSD-like effects from the intensity of the experience rather than acute LSD intoxication.

[deadbeeves]

You're talking about the half-life of the molecule in the bloodstream, which is different from the half-life of the intensity of the effects. Serotonin receptors begin to downregulate as soon as the effects start, causing tolerance which lasts (to some extent) for several weeks. Taking a massive dose of LSD, or any other classical psychedelic for that matter, wouldn't significantly extend the trip. The brain just refuses to stay in that state for long.