The coffee has been a bit strong so far, could we do a test run with less coffee powder?
Well. 6 grams of coffee per cup says the instructions. And the amount of powder increases linearly with the cups. By the way: If you squeeze out the last cup of coffee, you should cook a new one right away.
The amount of powder does not increase linearly with the amount of water. See for example the article here: https://fellowproducts.com/blogs/learn/the-golden-ratio-for-brewing-coffee