Point of collapse on Pitch Control

I know its the very basic of Acro, but you have to start somewhere right, and as I am only flying coastal, it is hard to progress further than wingover with only 50m underneath you.

I am pushing pitch control quite far at the moment, and I am wondering at what point does it have a frontal collapse during the surge forwards. How do I tell if I have gone this far, and how do I then brake it to prevent a collapse?

Also, whats the next step after dynamic turn in the acro school of learning?