Here's the 1H spectra of mescaline (taken from Hallucinogens - A forensic drug handbook).
There's no information on the book on what solvent was it used, if deuterated chloroform or what... Maybe its in the publication I cant find, which I write further down this post
You can also use the program ChemDraw to predict both 1H and 13C NMR spectra of different molecules, and usually its quite accurate. Here is the prediction for Mescaline:
Indeed NMR is very good for characterization of molecules, but it's not of too much use for identifying minor compounds that are together with other much more abundant molecules, unless you isolate it, at least that is my understanding of it. When I gave to a friend some jungle spice to NMR, the only thing that really showed up was DMT, there was nothing else identifiable, but as you can see in the
mimosa/jungle spice analysis thread, with GC-MS (or even TLC) one could clearly see other minor alkaloids. So for people doing forensic analysis where they also want to identify minor compounds without doing column work, or general analysis on plant mixtures and so on, I can see why Shulgin would focus on GC-MS.
In any case you can check our WIKI, I have uploaded already this NMR for mescaline in the
Mescaline Analysis subsection
Btw, other potential publications I cant really find but that should have mescaline NMR information is:
Spectrometric forensic chemistry of hallucinogenic drugs. S. W. Bellman, J. W. Turczan and T. C. Kram, J. Forens. Sci., 1970, 15, 261
and there's another one referenced in the book I took the image above from, but I cant even find the full reference name, must be in japanese:
Ono, M. (1970) Nippon Hoigaku Zasshi, 33, p. 339