Here are a couple of suggestions for reducing nausea when working with harmala / rue brews for visionary experiences:

1. Grind the Rue in a coffee grinder and put it into capsules to swallow. However, remember to leave some time before taking the accompanying tryptamine, so that the capsules can dissolve. Around 1/2 hour seems good. Also I notice from your post that you are taking 3-6 OZ(?) of Rue, which is *much* more than is necessary for a MAOI-enhanced experience. Most folks just take 3-6 GRAMS of Rue with mushrooms, which is around 1-2 teaspoons of ground Rue.
   
2. Consider using anti-nausea herbs such as MJ (still the best, although psychoactive in its own right), ginger, mint, camomile, dill, fennel, etc...
3. Plug your nose or put sprigs of mint up both nostrils while swallowing the brew. Smell alone can often induce nausea, so its best to avoid smelling something that has made you nauseous in the past. Fresh mint is especially good for this as it is highly aromatic and is also an anti-nauseant. If no fresh mint is available, try using minty toothpaste.
4. (this can be the hardest one) Embrace the taste of the Rue/Ayahuasca by actively programming yourself that it tastes good and is being taken for your heath and enlightenment. Hypnosis can often be helpful here, although the conditioning does need to be regularly renewed.

Happy tripping,
A