If you strike quickly, you can control the situation adroitly. Hands are hidden. Right or left depends on the situation. Moving from your chest, it is like a tiger catching a lamb. Strength put in hands should be instantly variable.
Elbows are to be lower than armpits.
I hand blows exemplify this principle. Keeping the elbows down allows proper kinetic alignment of the skeletal system for massive impact, and alignment of the sinews for tremendous kinetic potential. If the elbow is raised the flow of kinetic power is diffused at the shoulder and cannot reach the hand. Yin or Yang, left or right is up to the situation. Be natural while moving feet.