Caapi boils down to simple math (no pun intended).
10kg = 10,000g
10,000g divided by 500g = 20x potency (HURRAY! You're correct!)
The water to paste ratio is 20:1 or 20x potency.
A standard dose of caapi is 50g.
So, a standard dose of your 20:1 paste would be?
YOU GUESSED IT!
2.5g
Who knows if you have 20x caapi extract though. Perhaps it was only boiled for 10 minutes so that people can make money and most of it tannins. Always do a small dose test first just so you don't overdose. Alternatively, make your extracts and purify harmala crystals!