Aims: Atrial cardiomyopathy (AtCM) is associated with new-onset atrial fibrillation, arrhythmia recurrence after pulmonary vein isolation, and ischemic stroke. The amplified P-wave duration (APWD) as surrogate marker for invasively measured atrial activation time offers a promising non-invasive, cost-effective tool to diagnose AtCM. However, despite high sensitivity and specificity, APWD remains limited in clinical practice due to challenging P-wave offset detection in some patients. We hypothesize that electrodes closer to the atria yield P-waves with clearer delineation, enabling APWD measurement more accurately compared to the conventional 12-lead ECG. Methods: Body surface potential maps during atrial depolarization were simulated using 100~atrial and 25~torso geometries derived from statistical shape models, combined with 21~fibrosis distributions derived from electroanatomical voltage mapping. Unipolar setups (right-leg and Wilson's central terminal references) were optimized by identifying positions with high P-wave amplitude and clearly defined on- and offsets. Results and Conclusion: The optimized positions were located above the conventional V1/V2 electrodes and align with previous studies to improve standard P-wave recording. In conclusion, this work demonstrates that optimized electrode placement could improve APWD measurement, thereby enhancing AtCM diagnosis.