There have been other threads that have followed this theme of pharmaceutical or herbal brain enhancers for PR. I don't recall congamine being identified.
My general opinion is they are not necessary, and could be more of a hindrance than a help. If after you've got the system working, and you still want to see if it helps... just play safe.
I myself used Gingko, not espressly for PR, and even at less the recommended dosage it had some unsettling effects on me. I stopped immediately. I tried again about a month later and it happened agains, so I knew it was the Gingko and trash the rest. Others say Gingko does nothing for them. That was my only foray into herbs.
Ian2 