People always talk of the nuaseating effects due to the fact that harmala alks are very well known for causing nausea in high doses. That is usually referring to a dose large enough to completely inhibit MAO function, for activating DMT orally. With mushrooms, since they are active on their own, any amount of harmalas will effect the experience in some way or another.
With that said, every person is different in the way of what they can handle substance wise. A dose of harmalas that may make one person unberably sick, may only make me or you very slightly nauseous. This could be due to personal amounts of MAO in your body compared to another, or just our ability to deal with the discomfort compared to another. Either way, everyone is different.
Rue is also more sickening due to the other alks that are present, I can not remember the names of them at the moment though. They are even more known for causing discomfort. Compared to caapi, rue should make you more sick IMO. Thats why people usually will do further cleaning steps on a rue extract then they would on a caapi extra, to remove these extra unwanted alks.
I am sure caapi has some other alks in there as well, but not the same ones as rue. Rue can be considered somewhat toxic because of this, while caapi is usually not considered to be toxic.
Everything published by Gone-and-Back are the mad rantings and ravings of a mind who yearns to be free and thinks he knows what he is talking about. However, these are just delusions made to feel that freedom, because that freedom will never come. Any experiments done are purely figments of the imagination, and are falsified to the highest degree. Nothing should be taken seriously from a crazy mans mind.