69ron had some dubious information.. There is no evidence that there is any n-oxide in p. viridis, in fact, there is evidence that it is NOT there (I can search for the publication, I think it was from callaway, they analysed with hplc-ms many ayahuasca brews made with p viridis and none had n-oxide). Ron was speculating based on some idea he had that leafy plants have a lot of oxygen around and therefore there should be n-oxide, but that is most probably wrong first because of alkaloids being in salt form may be more resistant to oxidation, and also because there can be natural anti-oxidants present in plants.
In any case, i dont have any experience with psychotria extraction, but I cant see why it wouldnt work. I would not really defat, I would probably try to play around with FASI/FASA precipitation of alkaloids from solvent instead, like in BLAB tek fumarate salting step... Or go for naphtha pulls, see what you have left and either recrystallize it, or redissolve in acid, rebase and repull, or dissolve in acetone and do FASA to get fumarates. Defat is a very wasteful process, i would def avoid it at all costs and try other methods.
Also, if you are extracting from a leafy plant, cant you instead find diplopterys cabrerana (chaliponga) ? It usually has way more dmt than p viridis....
Be sure to let us know if you do try anything, whether it works or not