I am in the Pacific Northwest, but have traveled a bit, and am VERY serioua about my hash browns. I am of the school that potatoes should be parcooked for no-fail hashbrowns. (Spouse prefers country fries, slices or chunks of potato, cooked or not, fried with or without onions, green pepper, ham, or bacon.) I insist, after trying all types, on baked russets as my base potato. Raw lacks something, microwaved ones end up mealy, and boiled ones are just not as satisfactory. I grate my potatoes, with a slightly coarse grate. Riced potatoes are too fine for my palate. When I grate them, the skin removes itself in the process, so I have grated baked potatoes. I start them with about 1 T of butter for 2-3 servings. It browns and crisps well, and adds to the flavor. If I need a little more oil, because, perhaps, the cast iron wasn't well seasoned, I use vegetable oil (usually olive, but suit your preference) rather than more butter, to lower the fat content. Potatoes, if allowed, will soak up grease. Don't allow them to. The perfect hash brown is probably fried crisp on one side, then the other, and left soft in the center. I have been known, however, to turn them more than once. I usually turn them as a unit, rather than individually.
When the mood suits, I add onion. I use raw, finely chopped onion, and, by the time the potatoes suit my requirements, the onions are done. Occasionally, they are served with melted cheese over the top. The cheese has to be grated first, and a good quality cheddar, or it will not melt properly. Serve with egges, over easy, and toast. It is very easy to end up with a grey mess if you start with raw potato. The secret of the potatoes in a bag is just that they are par-cooked. They are not baked, therefore not wonderful.