Nightshades are pretty good to control when smoking, compared to oral use. I have talked to a few who did this and read a lot about it. I think the most fascinating story I found was about a Yogi who eats! Datura every day in order to keep up his spiritual learning. He claims that he ows most of his knowledge to this plant and is in an state of higher consciousness nearly all the time by  reapeted ingestion of his sacrament over the course of the day. I'll try to find my source about this one again.

Anyway, I have not tried it myself yet. I am fascinated about it for years and I have a jar full of seeds and plenty of dried leave but never really had the feeling of being ready to make a good use of this plant. I think working with Datura needs genuinely effort to understand what can be learned from it. I do not see any real recreational benefits from this substance and there are more comfortable alternative for most purposes. However When I have some time for it I will try some low dose experiments with Cannabis, since this seems to be a promissing combination.

An advise for save dosing: Get much plant material. Grind it or shred it really fine and mix thorough. This way you receive material with constant alcaloid levels which is almost never given with raw plant material. Then weight a certain amount with a good scale, start at low doses and wait several days between trials (with shorter intervals the previous dose will potentiate the next). IMO this would be a save approach to consume nightshades. "Always take x number of seeds" would be dangerous since even different parts of the same plant can have severly different potencys (up to 300%!).