That's how it works with just one tree. You put half of the paddles on one side, half on the other. Each shooter is trying to turn his paddles to the other side. At the same time. That's why it's called a "dueling" tree. https://www.youtube.com/watch?v=pg8SgVISP8g
Great example of dueling tree, awlful example of gun safety. Muzzle sweep much?