Qarel,
You wrote, on the Die-Out problem:
Just add 24% of the buy amount, instead of 50%, to PC (and calculate the minimum amount to buy or sell relaitive to PC, not to Share Value). The 24% is an approximation, and would change with a different Safe and Minimum amount
You are right that using 24% instead of 50 % would reduce the die-out, reducing it 0% will remove the Die-Out as the PC will be a constant and it will also be symmetric with the Sell condition!
The use of your safe(%) will still create some asymmetry but that is no problem at all: symmetry is not needed to create a good yield.
In regards to the Min trades: Is it not simpler to set Min Trade = Constant? The various type of stocks and the different trading costs would almost require this anyway.