Start with a comparable corner
Choose one corner and two clean laps in the same car, conditions, and fuel state where possible. Align the traces by distance or a recognizable track landmark. Then look for the first clear deceleration, not merely the first visible foot movement. Small pedal noise is not necessarily a meaningful braking event.
Note the approach speed and whether the car is settled. If one lap arrives faster, the same marker can produce a different result. Record what is different before deciding the braking point itself is wrong.

