Cut as soon as you see blonding, pretty well no matter what. early blonding can be a sign of stale coffee, or coffee that is way too fresh (too much or too little CO2 in the bean). Experiment with your beans at different ages, 3days off the roast, 5, 7, 9, 10, 14, 21, a month, and see what you notice. Also try dosing a little more into the basket. How do you currently dose/tamp?