Here is a link to some interviews by professional system builders. Those questions are probably addressed. This along with feed back from the guys here should help. Good Luck! System Builder Interviews
These words certainly ring true to me. I am guilty of trying to introduce elements from my "test bed" too quickly in the past. I have learned now also to have my seperate "test bed" and only gradually evolve my system that is now making a profit. Since my system of three years has evolved to the point where I am comfortable with it (what I trade and the time frame) I dont see it changing it wholesale. But many of the rules I have can be slowly changed over time with lifes experience.
Actually, that should be "thanks, PoundThe Rock". But I hope his post gets noticed. There's a fine line between tweaking and curve-fitting, and an even finer one between tweaking and refining. It should come as no surprise that a system will have to undergo at least some modification when put into practice. But it's very easy to wander off down some path or other that looks to hold more profit potential, then get so lost that one forgets what the underlying strategy is.