Victor Cova:
To make the question more grounded: I'm going to go spend a few years with Shuar Indians in Lowland Ecuador in a year; Something they may do (though it is possible they have now stopped) is to take Ayahuasca, a hallucinogenic, and dance, sing and talk to animals and travel to underwolds and waterworlds and forest worlds etc. Should I spend the year trying to get very very good at insight meditation etc so that I'll be able to better grasp what theyy're doing, will it be useless for that purpose but a good thing generally, or should I avoid mixing the two together?
If your aim is to 'better grasp what they're doing,' you'd probably find it useful to ingest Ayahuasca with an experienced, sober-at-the-time friend so as to understand the nature of the trip out of the context you may experience it in while in Ecuador. Insight meditation probably won't help you understand it any better unless you can get to anagami or so, and in that case, it will (at best) only provide for a more stable emotional state (which is important when doing such things, hence the suggestion above about having a companion). It would probably also intensify some of the effects in some ways (due to increased imagination strength which is a byproduct of concentration strength). If the above isn't an option, it would be a good idea to experiment with some other psychedelic (if you haven't already), in a similar manner.
By having experiences such as the ones alluded to above, you'll likely be much more stable and less "suggestible" on later trips. For example, if you experience "something profound" while in the "underworlds--" and you had not had previous experiences to give it context-- you may walk outta there believing (or at least open to) all sorts of madness. If, however, you've previously experienced "something profound" when in the "spaceship" that your bedroom transformed into, you'll be in a much better place to understand the alterations (ie: that the "underworld" was a cave in a jungle on earth), what they mean and don't mean, be able to enjoy the experience for what it is without confusion, and so on.
Enjoy,
Trent