How do I set a Step Back auto-green?

Switch the Step Back page On. In game, tap D-pad Down. In yew's words it "automatically activates after clicking down on the d-pad, performs a step back and times the shot for you."

The shot value runs 100–1200 ms in 5 ms steps. Default is 660; yew runs 710. Early → raise it, late → lower it.

The Step Delay page controls how long the script waits after the step back before it starts shooting. If your step back animation is fast, lower Step Delay; if it is slow, raise it.

Source: yew2K mod menu; yew's published settings.