Not sure how helpful this will be, but I will share my experiences with it. I have had to deal with arm splap my whole shooting life. For some reason, my left arm rotates when I draw, and the inside of my elbow ends up pointing directly toward the string. As part of my routine, I have to rotate my arm clockwise to get my elbow back in a normal position. If I fail to do this, WHAM!

When I do have slap, the arrow hits low and left EVERY time.