SETUP: Set a bench to a high incline and lean forward into it for support. Cables should be set just higher than shoulders, and we don’t need any handles.
LIFT: Take an underhand-grip of the cables (with left cable in right hand, and right cable in left hand), then move the weight by moving your elbows out & back, squeezing the muscles of your upper back.
TIP: This angle allows you to work the rear delts without hitting the rotator cuff, which should mean a heavier weight for you. An underhand-grip will force you to work harder as you fight to maintain good posture.