Indeed, exit rules are very difficult. I don't know how will perform my new exit rule, I'll need to have the discipline to stick to it. But I'm changing rules from time to time when I learn new things, so I don't know...
I think I don't remove my trust in the trader, not at this stage. I haven't discarded these darwins, just put them aside for a while. I know that every trader in the darwins that I removed this time is working hard; they talk in the forum and I see their efforts (excepting PMZ, whose owner is unknown to me, but I guess he's also working). For good or bad, I'm a very emotional guy and I really feel bad for the human behind the darwin when I remove such darwin and I see the hard work. But I have to do something to try to improve/stabilize my returns.
Actually at this moment, remove any of them is being difficult as hell, because I think they are very good darwins (and also because my portfolio is shrinking too much). I have opposite feelings and the only thing that I can do is to try, and continue learning while (hopefully) I don't lose too much.
Also, honestly DD bigger than 15-20% scares me. I don't need/like to take too much risk.
I see (good) darwins like an SP500 index. I mean, each darwin would be a different index, one SP500, other (imaginary) AA300, other BB400, and the other CC600. SP500 and every other index has an upwards bias. All of them will go upwards because of internal forces, but from time to time, all of them will experience drawdowns and bad luck. What we want is to find those darwins whose wins compensate the other loses, to avoid the turnover as much as possible, and to get the straightest possible upwards line.