As I said earlier, figure out what your peak load is: how many showers running at once, how many back to back, is there a big tub that needs to get filled, do you want to be able to be using hot water with the DW or WM running at the same time? Then, and only then, can you figure out what you need. Say all four showers are running at the same time, that's about 10gpm. 7-minutes, and a 70-gallon tank is essentially cold, especially in the winter when you need more hot to cold ratio to keep things comfy. Fill a 100-gallon tub, and it won't be hot when you get in. We can't tell you what you need until you tell us your intended use. Some big WH may have slow recovery, some have MUCH bigger burners, and can help to maintain temp with a modest output. Raising the WH storage temp makes the tank 'look' bigger, but once it's cold, it's cold, regardless. Where I live, I've personally measured incoming winter water temps at 33-degrees. So, my wintertime hot water needs is more stringent than someone living in say Honolulu when the water temp may be 70-degrees all year long. If you have a deep well, regardless of where you live, your water is likely cold.