Set your flour weight and dial in hydration, starter and salt as percentages. The gram amounts follow — no mental math at the counter.
How this works: everything is measured against your flour weight. A recipe at 75% hydration and 20% starter means water is 75% of the flour's weight and starter is 20% of it — the same logic professional bakeries use to scale a loaf up or down without breaking the recipe.
Not the textbook definitions — the things that actually trip people up at the counter.