For me, I can occasionally get something from a single fragrance, it it's a very distinctive note and it's super-obvious, but usually it takes at least 2 fragrances for me to tweak out a note. I got guaiac wood in 2 fragrances (Tokyo by Kenzo and Bulgari Pour Homme), and when I smelled the real thing as a pure component, it turned out I was right.
I think that Vétiver Tonka was a perfect frag to reveal vetiver, because Jean-Claude Ellena keeps his compositions simple, although I'm not sure how simple VT actually is.
All the recent iris scents, especially the Pradas, make iris easy. Creed EDTs are excellent for getting their various main natural components. Violet frags are easy, too. You may just need one, but two will do it for sure. Jasmine is pretty straightforward. Rose too.