I think the main issue may be the concentration, which is quite important for this step to work properly, 250 grams of caapi is not a whole lot.
If it doesn’t work the way you’ve tried it so far, my suggestion would be to base everything first. Then collect whatever precipitates out and dissolve that again in a small amount of vinegar and water, using a much smaller overall volume than before. After that, you can perform the Manske step again.