I think you saw the caapi tincture thread i started...
I have used a previous/simpler tincture process to add to my changa (using black caapi). The changa is amaaaaazing. That previous tincture batch i used was pretty weak, so it didn't extend the experience in terms of time. It is closer to a pure dmt experience but with a very crystal clear filter of ayahuasca. Absolutely wild experience with crazy vibrations. But, as soon as my new batch of freebase finishes up, I'm going to start my next batch of changa using my latest tincture process, which I feel will be more effective in extending the trip duration. I may also, as is my intention with the next tincture I make, fortify it with some extracted rue alks....
anyway, I've been somewhat obsessed with answering both of these questions lately and feel i'm getting somewhere rather exciting, hope that's of some help.