I took 10 bottles at once, mixed with a cup of water. I puked about 30 minutes later. My guess is I should have spaced them out to avoid puking. After my experience, I firmly believe the people that passed were dosed gradually. It's got to be absorbed and my guess is the lethal dose depends on your health. There is little info around the web about this and since it's purpose is to constrict the flow, I don't think you can calculate the "lethal". I imagine if I would have exercised my body would have had a different reaction too, but I laid in bed waiting for death after I puked. I feel strongly it can work, just going to have to have more bottles, space it out, drink some booze and maybe do more activity to force my body to struggle. I didn't get medical attention and it's been a week, so who knows, maybe I gave myself a blood clot somewhere and there is still a chance.
I feel like you are right in the gradual part and it doesn't stay in your system but maybe 24-48 hours (from research I did). Feel like it needs to be heavy doses spaced within hours, might take a few days might take a few hours. It's at it's peak within 2 hours (from research I did) so it depends on how much, how often, activity, current health, and if it's combined with anything. It's damn near $7 a bottle, so it ain't cheap to pull it off.
It did not make me shit, puke yes, but only once. It made me lethargic, definitely wasn't begging for a button to press, only wish I wouldn't have taken it all at once. Didn't go to hospital, no one noticed. Drove a car 24 hours after. The worst part was the anxiety of the waiting for something happened and then being pissed I wasted money on 10 bottles for nothing.