Salvia was still legal when I first tried it. I'm not sure if it's federally illegal now, or just state by state. I remember the first time, after I was "back," I thought, "Whoa, this stuff is insane to take!"
I read up on salvia yesterday and the site that I was reading said that salvia is a dissociative psychedelic, so I suspect it has some of the delirium aspects that you wrote about, because I lost all awareness of who I am. It's like I had been detached from life and the little people kept telling me that I had really done it this time, and I was totally screwed.
I don't think smaller amounts of salvia works the way the smaller amounts of datura do. When I smoked a smaller amount of salvia, I couldn't distinguish any change in myself, but when I hit minimal dose I was off, and it was quick to come on also!
I think it's good to have someone with you if you try it. The second time I did it, my GF was with me, and it was a little less difficult for me on the return.
This link takes you to a page where those who have experienced salvia tell of their experiences; they're pretty interesting. I've seen artwork made by trippers, somewhere also. I thought it was the same place but maybe not.
https://www.erowid.org/experiences/subs/exp_Salvia_divinorum.shtml