I think "cut with boiling water" means water added
after the coffee has been brewed. (So an 'Americano' is basically an espresso cut with hot water).
But Metatron is right... using less grounds won't make it better.
I think the standard is about one rounded tablespoon (20ml) grounds per 200 ml water, or 1 level tablespoon (15ml) per 180ml water.
Final product is affected by quite a few factors...
* Type of roast (medium roast is slightly more acidic, dark roast slightly more bitter).
* Temperature of water. Too hot (boiling) and the coffee oils can be "scorched". Not hot enough and the bitter flavors might dominate. Ideally, water temp should be just below boiling... in the low- to mid-90s (Celsius). Many recommend that you bring the water to boiling, then remove from heat and allow to stand for about 30 seconds before pouring over the grounds.
* Duration of brewing is perhaps most important. Too brief and the sugars and dextrins are not properly extracted, resulting in a sour (acidic) cup. Too long and more of the bitter compounds are extracted. Brewing time should be about 4 minutes, regardless of whether one is using French Press or pour-over. (Some recommend 5 minutes for medium roasts, 4 minutes for dark roasts).
'Angels' Cup' has quite a lot of info on it, nicely laid out...
https://angelscup.com/blog/taste/coffee-extraction-sour-vs-bitter/ 