I have always smoke Salvia. I quidded a few times with dried leaf. It worked but was mild. I noticed with quidding I needed no distractions. Any little noise was irritating. That is the same for smoking, but I can find a dark quiet place for 10 minutes unlike the hour or two of quidding. I need to get the set and setting better.
One day I will quid with fresh leaves. That I wait with anticipation although i do like the short propelling effect of smoked.
But Salvia has been an ally of mine and although I am not sure about the oral effect of an extract I can say a few definitive things (for me) that I have realized.
It can have a pain killing effect. A numbing of physical pain but mostly emotional pain. I remember I was so bothered by something once and I smoked Salvia and it took that issue and stuck it way back in my mind to get it out of the way. It totally shielded me. In the afterglow the issue was such a small issue yet I realized it had controlled me the last week or so. That amazed me.
I remember one time I had shoulder pain and had Salvia session and it put the pain to the background. I am not sure of this is an effect of kappa stimulation or just a mental consolidating it does. But it can put things in the background. At least for the session and afterglow. There are pain killing qualities.
It is so powerful that I am willing to bet it can be used as an ally for certain withdrawals. I tried it for opiate withdrawal once and it helped. I have no benzo withdrawal experience so not sure what it could do there.
Salvia is powerful and can be a great ally. I would for sure ask for it's help in any withdrawal. Excellent thought to use it. I am surprised Salvia is so passed over. It has helped me more than I can say. The way it rearranges reality, ask it to come out of the trance free of benzos.

You never know.