naphtha and bestine are pretty poor solvents for harmala.
As ive already expressed before, Im doubtful even about IPA. I know in practice a lot of people do it and it seems to work well, but chemically I wonder how much of the alks are actually being pulled. I say this because I've tried dissolving freebase harmalas in IPA, and they dont dissolve too well, and in caapi, the alks are probably in some salt form. AFAIK we dont actually know which salt form the harmalas are naturally in caapi, but there is the possibility that the salt form is even less soluble in IPA than freebase. This would mean that people are losing a lot of alkaloids if they just soak the caapi and then throw it away.
I would love if someone would do an A/B in supposedly 'spent' caapi to see how much more alkaloids can be retrieved.
So summing up: Between your options, def use IPA. But if you do this, then at least do more than one soak with IPA to hopefully get more alkaloids.