1. When you refer to pharmayuasca or ayahuasca what you are refering to is the ratio of harmala/harmaline/THH. If you extracted each varient of those and dosed independantly you would feel the difference, this is achieved via varying PH levels in the basification stage. You will find that the more you have of either one the more tired and stuporous you will become. I have found from searching on here mixed reports about personal preference over which one feels more less teaching, guiding, or "grounding". Some prefer rue, some caapi.

2. That makes no sense, you can't have pharma with caapi alkaloids, that would make ayahuasca. caapi=aya / rue=pharma. You really have to distinguish here that there is no other component to either a brew or an concentrated extract, it is the SAME compound... Harmala/Harmaline/THH

3. The same as number 2

4. Once again you really have to distinguish here that there is no other component to either a rue brew or a concentrated extract, it is the SAME compound... So the middle ground would be taking harmala alkaloid in any format. If you are thinking of taking high doses of rue like 500mg+ then you would want to think of extracting it, even if you dont want high doses you want to exract it... nobody like vascine, especially not pregnant women lol.

Side note: I have never heard of people taking 400g of caapi... perhaps you are thinking of a brew that is divided amongst 5 people. That high a dose would send someone to sleep before having an absolute vomiting fit