Why does the Optimistic results show more trades than my pessimistic results?
It depends on the strategy. Optimistic method may show more trades for some strategy and less for other.
Can I rely on the information that my Optimistic results give me?
Generally, Optimistic and Pessimistic methods will show equal result for backtests without ambiguous bars. The presence of ambiguous bars means that FSB doesn't have enough info for deciding how to execute orders properly in a such bar. By default FSB uses Pessimistic method and will show less profit. But the true must be somewhere in the middle between Pessimistic and Optimistic methods. Use Comparator tool to compare the different methods. You can compare all methods or only Pessimistic and Optimistic ones. The middle line of the Random method must also be near to the real balance line.
How is the Optimisistic and Pessimistic relevant to my automated trading?
There is no connection. FSB doesn't store used backtesting method in the strategy file.
As a general advice, I can say that you may try reducing the number of ambiguous bars of the strategy.