Hi there and welcome!
There may be some information of use in this thread:
The caapi alkaloids (at least the 'normal' harmine and THH - caapi has a bunch of other slightly more complex alkaloids as well) may prove to be a little tricky to keep in solution. Don't let that put you off though - you'll surely have fun joining in with the experimentation.
Just be careful to avoid mentioning sources of materials other than live plants or seeds, please! More details here:
Attitude Page - DMT-Nexus Wiki
Pre-dosing with rue seed (or caapi) before vaped spice can be achieved in numerous ways. Tea, whole seeds, ground seeds - with or without encapsulation - sublingual, vaped whole seeds (see starway7's posts), whole seeds in a pipe, harmala enhanced leaf... the list goes on.
'Best' comes down to a matter of personal preference - the taste of the tea is quite challenging for many people, and smoking isn't for everyone either. These days, personally, I'm happy with mixed rue alkaloids after 2× acid/base cycles, redissolved in a little vinegar. The taste is just awful enough to make me feel like I'm earning the benefits :lol: It can be hidden - more or less - in peppermint tea with a teaspoon of honey.
I haven't worked with caapi nearly as much as I would have liked to but the taste can be somewhere between rather more forgiving and just as terrible when compared to rue depending on the exact method of preparation.
5 drops of a tincture sounds like not very much of a dose at all. You'll get way more mileage out of it if you use it sublingually - keep it under the tongue, don't swallow it for as long as you can manage. It would be helpful to know just how much caapi went into that 10mL of tincture that you have, otherwise dosage information is plain guesswork.
