Thanks Andrew.
Your answer 1 did solve half of my question 4 also ;-)

I still am a bit confused about your answer 5:
The Zs are fixed black-box-strategies which are given to us since years, so shouldn't they all be obsolete by now?
It seems to me that it is just a matter of luck to find the right asset to trade with and then running it, until it seems not to be lucrative any longer.
However, this is exactly what was not told to us in the manual - we were told to stick with a strategy and not pull out when we are scared.