At some point, you just try to make it with whatever you think "a handful" is and measure when you do. If you fail, you note and adjust. After a while, you kn

At some point, you just try to make it with whatever you think "a handful" is and measure when you do. If you fail, you note and adjust. After a while, you know that it's situational - unless it's salt or leavening agents(yeast, baking powder, etc.), there is a bit of wiggle room to adjust things.