I’d assume the quantity of nutrients consumed is determined solely by the amount of Huel used, not by the amount of water added to the mixture. I tend to stick with 200ml:1 scoop for my “Goldilocks ratio” (i.e. just right), but sometimes I reduce the amount of water if I want to make the mixture thicker and feel
Water has nothing to do with the nutrients. You can even eat the powder with a spoon, without water, if you want…
Just try different amounts of water, and choose the thickness, or watery taste, you prefer. Try letting (or not) the shake rest in the fridge, too. That really changes the taste.
As everyone else has said, the amount of water you use doesn’t effect Huel at all. It just affects how thick/thin your Huel is. Make sure to drink plenty of water throughout the rest of the day though!
Using less water will make the Huel stickier, meaning you’ll have a harder time getting it out of the bottle. This means you might get a lot less Huel, and thus less nutrients, than you planned. I recently weighed my bottles at the end of the day and found I had 160 g of Huel left in three bottles. Maybe two thirds water, is my guess, so I had been getting about 200 kcal per day less than I thought.
So yes, using less water can have a downside when it comes to the nutrients.