In the thread about safely dosing datura, godsmacker states to have had a terrible experience with just 3 datura seeds.
But there are multiple threads here, some very old, some not that old, where the use of datura seeds is being discussed. And i must admit that i have used datura seeds as an additive myself, with ayahuasca, with shrooms and also with LSD, because some guy named 69ron has repeatedly stated here that this is perfectly safe.
So maybe it's a good idea to look at all threads where the use of datura seeds is being mentioned.