... it’s very hard experimenting when you’ve no idea of potency or dosages.

This.

Fun thing I bumped into a few weeks ago: the guy who's credited with inventing LSD tried a bit to see how it worked and how it felt. But he had no idea just how ridiculously potent LSD is. I forgot the exact numbers, but I do recall the ballpark. So he had a Fermi-estimated 100 μg while he only needed like 10 μg for a good time, so not only did he have the first known LSD trip, he had the first known bad trip.