What to expect from a trading system ?

["Henry Amand" <back@xxxxxxxxxxx>]

Hello, i have a question for you since you have more experience
in this than i have.

What is the highest percentage i should ask from a system before
i start trading it ? When testing i come to a nice 60% but, being with
optimalisation, and optimalisation is always for the past, that seems
to be a little low. Ofcourse i can imagine if that 60% of the trades
make, say an average of 25 points and the losses make only 5 points
it's a good system. 

But, ofcourse that can go fairly fast to 40% winning and then it is not
that good anymore.

So what should i expect when backtesting ? and what should i aim for ?

Thanks in advance,

Greatings

Henry Amand