I started by weighing out each scoop so I had a rough idea of the amount, but now I tend to just throw three level-ish scoops into about 400ml of water. Once you’ve been at it for a week or so you get a good idea of what works and what will fill you up.
Well Huel is just food. It’s kind of like if you made a massive lasagne and you went online to ask how much you should have in the day. Well… I could probably eat 1 slice for breakfast and two slices for lunch, but I’m sure you might be different? And how big is a slice? You see why it’s difficult to answer
For what it’s worth I have 3 Huel shakes per day, each 2 (heaped) scoops
Huel is great for weight loss. Lots of people on here (me included) use tdeecalculator to work out total daily energy expenditure then MyFitnessPal to keep track of calories. Eating at a 500kcal daily deficit should lose you 1lb of fat/weight per week. Good to invest in a good set of digital kitchen scales too, rather than rely on scoops. If you’re really determined, as I was, it helps to weigh everything you eat, otherwise it’s a bit hit and miss…mostly miss.
If you type weight loss into the search box above you will see lots of threads on the subject. Good luck!