1. I would first make a Shadow Clone of myself and stand next to it side by side. We be facing each other with my right foot and his left foot out in front. Are knees are slightly bent with my right and his left palm sticking out hyuga style. We then charge chakra in our hands that are behind, so could get ready to use the Eight trigrams empty palm technique. At the same we move our back foot and hand in front us in one giant step and release our technique at the same time hand to hand.
You can do this technique by itself by using both of your hands. First you put one foot in front of the other so you can maintain balance when you release the technique out of your hands. You bend your knees slightly and bring your arms back all the way until both of your hands are touching the side of your chest. While in this position you would then send chakra equally to both of your hands to do the Empty palm technique. When you are finish, you will take your back foot and take one huge step forward and at the same strecth your hands outwards and release and combine both empty palms to make the Air Wall Palm.
2. I would use this when my opponent sends a wide scale technique my way and when he/she summons a large creature.
3. After I release this technique, I would spit out a huge fireball (or any s- rank fire jutsu that comes out your mouth) to combine with it to make it withstand other elemental techniques since that is its weakness. Another one is: after releasing it I will run behind and use it as a sheild to conceal my postition from you. After my opponent blocks it and cause a huge explosion, I would use the Eight Trigrams Aerial Attack and jump over the explosion, and my opponent will probably be covering his eyes from the explosion so he notice me up in the air.
4. Pro- Its a wide scale attack, and can go long range. Con- You can't redirect it if you miss.