We use roughly 2 cubic feet of granulated carbon and filter about 10,000 gallons.
But seriously you do see your asking a un answerable question. What might be filtered enough for you may not be enough for someone else, or vise versa. Your distillate might not be as pure as someone else or more pure. How do you ferment? fast and hard? Slow with lest off flavors? How many plates are you running? How good are you at running said plates? Or do you just think your good at running your still?
Just do what you think works for you and call it good the thing with this business is there are very few hard yes and no answers.