Yeah caapi first and then both together next day I would say (if you have enough caapi to experiment first with just it... )
40g is dry caapi weight before doing the 3x (not just one) boils in the material.
I preffer psychotria in comparison with mimosa for oral use, in the very least because of taste (mimosa tastes soooo bad), but also there's this "romantic" thing about psychotria+caapi being the more common/original brew, mimosa is from a different area of Brazil its not even from the amazon. Not that this necessarily matters because we can always invent new things but somehow all the experiences I had with psychotria+caapi felt really right. It might be self-suggestion though, and also most trips I had with caapi+mimosa went also great (psychedelics hurray!

), but for some reason it feels for me that caapi+psychotria or extracted harmalas + extracted dmt are my ways of doing this.
Another thing to consider about mimosa is that its very very strong in terms of dmt content, so one gram more or less might make a lot of difference, making "overdose" more possible (which is I think why some people seem to feel mimosa as very hectic when consuming orally, I dont think mimosa is bad per-se but there are these issues of very strong potency and taste at least).
And no Ive never tried any acacias orally, if you do be sure to tell us how it goes. Just remember to first experiences start with low doses.
Good luck!