I never tried DMT (yet!!) so I can't really compare. But I think I get the idea.
You can actually stay grounded with salvia, but in my experience, it was more like I needed to find the right "position" : it was like Salvia was taking me in a certain direction and if I didn't postion myself in that direction, I would only feel the physical pressure that most Salvia users report. Then, after a few attempts, I did find the right position (not an actual physical position, but I got through a lot of funny postures trying to find out :roller

and BAM! I went straight into Salvia space.
Like many others, I believe you have to learn about how to use Sally, but once you get it, you can breakthrough very easily and with something like a reverse tolerance. I can now get a full-blown trip with only 1 or 1 1/2 bong hits whereas I used to need 2 or 3 (last one was kind of difficult to perform). It's just a matter of you and her (?)getting acquainted (not sure about the spelling, sorry)
About the setting, I like to be in a dark or dimly lighted silent room, alone. I do close my eyes, as I have never been really interested in visuals with psychedelics (which in my opinion hardly, if ever, occur). It helps you focus on your journey.
Hope this helps and answers partly your question.