Not going to try to convince you not to try Datura. It is unlike anything else and is definitely transformative.
I advise going as low as you can in dose. It is toxic, and a bigger dose increases the likelihood you don't remember anything and can't integrate the experience (Why do a drug if it will be like you never did it in a week?). Plus, as everyone else mentioned, the body load from Datura is immense. Better to aim small and do it again in a couple months, which will prepare you. Also, if you find out you don't like it at all (quite common), you won't have to deal with a much longer trip.
It is also easy to overdose on these things because the comeup can be very slow (like Mescaline in some people). There is also a lot of variation from plant to plant in strength. I advise making your tea with 5 seeds or however many you think is appropriate and taking just a sip every 15 to 30 minutes, having your friends take the tea away when you start acting weird/become red or putting it down yourself when you feel something.
Don't follow McKenna's dose advice when it comes to something this powerful and toxic. Be careful, and it can be a lot of fun and very interesting. Make sure you have a full week of nothing much to do, because many people feel weak for several days after a two-day-long trip accompanied by an intense fever and dehydration.
Have fun!