If you’re concerned with maintaining ratios, volume isn’t going to be very precise when one of your ingredients is compressible (flour) and another isn’t (water). That said, the ratios used in baking are often less sensitive than people like to insist they are. Before we had recipes insisting you need to measure your flour down to the milligram, people learned how much flour to add by learning how wet/sticky/elastic the dough is supposed to feel when working it. Bakers learned by trial and error how wetter or drier doughs behave and how to get a preferred result, and then passed that knowledge on to their apprentices.