Please take a look around the forum.  Do a search for "pharmahuasca" and "oral dmt" and I think all of your questions will be answered.  Herbal MAOI's are 100% legal in the US...there are more than a few that will work.

Caapi is the most pleasant herbal MAOI I have encountered.

Oral DMT dosage is based on each person. Some take 25mgs and are blown away, others need 200mgs+ for a mild experience.  I cannot give dosage recomendations because of this.

Crystal DMT + an MAOI does not equal ayahuasca.  Hausca = Vine....so unless there is Caapi in the brew it is not Ayahusaca.  The effects are simliar, but not the same.

Please search the forum.  There is SO MUCH INFO here, all you have to do is look.