Hey dear @crosheille! It's really easy to make it and I feel its kind of making instant oatmeal as well. Just mixing the oats with milk and leave them in the fridge for tomorrow morning. Plus adding some fruits.... I really encourage you to try making overnigh oats. Search on google/pinterest. IT's FULL of great yummy recipes, get some inspiration and try making some.
Well, Yes. I eat all the portion. Making it so often, I know how much I can eat so I don't usually go wrong with portion sizes.:D
And Idk what to say about what oatmeal I could recommend because there are so many on the market plus you leave in US? (I can't remember for sure), me in Romania. You have different stuff there. But me, I always go with old fashioned oats, whole oats and sometimes quick oats. I don't buy prep oats. Granola is fine, I buy that too. I have it with yoghurt. Yup.

Thank you for stopping by! Cheers and hugs!