Anytime I cook a new thing I like to follow the instructions on the package. If I'm only cooking it for me, I figure out how many servings their directions are cooking for and divide the portions by that much so there are no leftovers. When I followed this for the oats, it made them so thick that the spoon could probably stand up in them, even after adding additional milk.
So, I adjusted the portions so that I got a consistency that suited my tastes better. That's what cooking is all about-adjusting recipes to your preferences, after all, they've been developed by one person, or a team of persons, and no two people are ever alike.
Take a spaghetti casserole that my MIL used to make that was a favorite of Hub's. She would put the cooked spaghetti on top of the sauce and then put cheese on top before baking. This would result in some of the spaghetti being dried out, so I reversed that-I put the cooked spaghetti on the bottom and the sauce on top-still tasted the same, but the spaghetti wouldn't dry out.
And like another favorite of his-the recipe called for raw hamburger meat to be pressed into a pie pan, baked, then filled with a mixture of mashed potatoes and cubed Velveeta cheese. I adjusted that to forming the hamburger meat into patties, placing them on a cookie sheet and baking. Then I would spoon mashed potatoes-seasoned however I felt like-then shredded cheddar on top, pop back into hot oven to let cheese melt. Hub will eat two of them and would eat it every day of the week if I made it. I usually ate one to keep from eating too many potatoes at one sitting. how many potatoes do you spoon on? Well, use your own judgment, I hardly ever measure unless measuring is imperative-such as with hot cereal like oats, wheat or grits.
One other thing-if you're in a hurry for breakfast and still like steel cut oats-try something a lot of people I've read about do-cook them in the crock pot the night before. They say that you can store it in the fridge in serving-size portions and it microwaves great. I haven't tried this yet, but I might sometime.