Higher voltage, lower amperage will save you money. You'll need less equipment and less weight in copper wiring. It is easier to find cut off switches and breakers for low amperage high voltage DC than it is to find extreme amperage low voltage DC breakers and switches.
It is realistic to use low voltage high amperage DC only if you are
energy sipping. An RV or shed might be suited. A residential home will not be.
Have you done everything you can to reduce power consumption? That is always the first step. You can't properly size a system otherwise.