well people certainly dose up on crystal. if you are talking about the thumbprint "initiation" thing most of that is all hype and urban legend. way back in the day on dead tour, there seems to be some accounts of the wholesale distributors dealing with crystal doing this sort of thing, but honestly, when people travel around the country taking massive amounts of LSD all the time, all sorts of strange things go down. the chinacat thread and all the hype around thumbprints and the "family" kind of turned it into some kind of internet hippie iconoclast, but from what i understand the reality of it is far more loosely connected and nothing to do with silly rituals. people ritualize things all the time, but its not an LSD or a "family" thing, its a some people who do a lot of acid anyways kinda thing.
i know people who are really into tour that will take up to 10mgs over the course a weekend run of shows or a festival. i think tolerance and the so called "saturation" has a bit to do with it. a lot of people who take "heroic doses" (i hate that term) often have quite a bit of tolerance anyways. i havent tripped for more than a few days in a row, but IME i reach a sort of psychedelic baseline of "normal". i think once that happens its a bit easier to dose higher
my advice is if you wanna do a thumbprint, eat a whole strip first. if you arent totally insane or not willing to dose up that high again, take like five of them.
i seriously doubt eating half a sheet or so is gonna be much different than doing a thumbprint