When you hit the foam pile, be ready with your first turning stroke. The angle is wider than you would use to drop onto a smooth wave because you want to get to the top of the wave. Take a couple of strokes before you hit the foam pile to slow your downstream momentum and to reduce the impact when you hit the foam. When you feel your boat near the peak of the wave put in a hard front sweep to overcome your downstream momentum and start you first turn. However, I find back shredding to be pretty hit and miss.
Timing is so critical and with a narrower field of vision there is more guesswork.
Both of these strokes have good leverage and are very powerful. But for even more backwards motion, use a cross forward stroke with the blade pitched by rotating the top thumb back. The back draw or back sweep can be used for that same turning direction combined with upstream motion but it is a weaker stroke because of less leverage. This move will work on any breaking wave or hole from six inches to greyhound hole size. The flatter the gradient downstream, the wider the peak will be and the easier it will be to find the balance point.