I would avoid using mixed n-butanol/ethanol as extractant, if possible, since the intended separation of a n-butanolic fraction from a mixed n-butanol/ethanol/water extract would be somewhat cumbersome. The system n-butanol/ethanol/water forms azeotrope (*).

You could perhaps consider to first obtain the ethanolic extract, dry the residue from ethanol, re-hydrate and extract the aqueous fraction, to finally extract the n-butanolic fraction essentially free from ethanol. This last n-butanolic fraction could be dried from its water content, if required, as I have discussed elsewhere at this forum: https://www.researchgate.net/post/How_to_evaporate_N-butanol_fractions

(*) http://www.ddbst.com/en/EED/AZD/AZD%20Ethanol%3B1-Butanol%3BWater.php

Thanks

http://www.berkem.com/en/expertise-en/plant-extraction