I recently came into possession of a 1:40 caapi tincture which apparantly contains 25 mg mixed caapi alkaloids per ml, a total of 125 mg. Would that alone be sufficient for activation? How about for actually being a legit ayahuasca experience instead of just oral dmt?

I think you need somewhere around 200-300mg of harmalas to activate oral dmt.

Yeah, caapi alcaloids aren't as powerful as rue alcaloid (harmaline) to activitate dmt. this can be good microdose or cubensis potention however.
I thinck the conscensus here woulmd be that a legit ayahuasca experience would be with the tea. Alcaloids extract are called pharmahuasca.

Ok then, what about the dose for harmine HCl? How much harmine HCl would I have to add to 125 mg of mixed caapi alkaloids to make it viable for pharmahuasca?

Edit: I just read more carefully and saw the 200-300 dose range. So, around 175 mg harmine added to the tincture will be more than sufficient to activate the DMT.

I suppose my question to those who have used caapi tincture and/or purified harmalas, how does it compare to the respective sources? Would a sufficient dose of caapi tincture have the same psychoactivity as caapi itself?

SWIM made this tincture

For me 150 mg Caapi TPA is sufficient for oral activation of spice. This is different for everyone. A friend of mine needs 200 mg and another 250 mg. A good way is to start with 150 mg and your amount of spice. Then redose with 50 mg and about 30 mg spice till the state wished for is reached. It is very nice to dose with the Caapi TPA and control where you wanna end up. It should also be available now as TPA in powdwer, not in a tincture, a better deal and better for these purposes. The tincture is more made for micro-dosing.

Good luck