It seems like it is an amplifier for both duration and body high.  I don't have many visuals with Mushrooms, though on Rue + Mushroom Alcohol they seemed to be pronounced in the back woods.

Rue is just rough.. compared to caapi (thought I've only had Caapi with Ayahuasca).  I know at least 4 people who thought they OD'ed on Rue by taking a small amount like 4-7 grams. (200g was the LD50) heh. (I was among them, "What did I do!" ).

I just remember praying to the porcelain god when I did Hoasca with Rue and ACRB.  It was just .. yuck.

Caapi seemed easier to keep down and only had me throwing up.

I think 3 g rue tea strained, then 20 minutes later 3 ml (1ml/1g) alcohol gave me some spectacular nights.

I've never purged on Psilohuasca, not even entered my mind.  Even on Rue.