Optimal write current of a data storage device is determined by writing test data with an initial write condition and evaluating a performance related to the pole tip protrusion (PTP) of a magnetic head. A PTP control duration is determined as a duration between where the test data is initially written and where a performance evaluation value begins to satisfy a threshold criterion. An overshoot value of a PTP control signal that determines an overshoot amplitude of a write current and a PTP control duration are determined by for writing subsequent data such that PTP-related data errors are substantially constant regardless of write time.