Markets are pretty efficient, just not all the time. you can make a lot of money with a 51% win rate system assuming a 1:1 RR as long as you do it often enough and are diversified. 55% win rate is gigantic. I see many traders trying to increase their win rate by being more restrictive in their parameters, which reduces frequency of trades and destroys statistical significance of their results. high win rate systems typically lose money through a couple of very large losses, which are unpredictable but surely to happen. you end up with a nice looking system on paper, but it's not realistic and you will instead lose a lot of money...it's not easy to take money out of the market!
True, and they become highly inefficient when they are trending. That's why most trend-followers can extract good money from the market with a mere 30% winning rate.
Hundreds is not a lot. Especially if you have only traded with one or two specific market "personalities". Not sure how long you have done your strategy for but I am assuming not too long if you only have hundreds of trades (this is why I assume you have only traded in one to two market personalities). If I were you I would be looking into what the variance, skewness, kurtosis of my trades were, for a start. You can do basic student T distributions in Excel to see the confidence on your average trade. Assume the actual confidence is significantly wider (due to the likely fat tails in your strategy and the markets in general), then you will see you need thousands of trades before you can even consider the possibility you are a winner in the long run.
%% Last one [#3] sounds about right; generally i would not aim @ 66.6 %rate. Its too hi or keep reading\ sometimes too low. i had a friend that lived @ 665 address. Rich man/family, but one day he said\ good thing it was not 666. LOL + true. You can do better than 66.5% some times but make sure all your drawdowns are not 66.6%. Good thing i took out of account enough to buy a car last DEC; JAN was major trend change\ so auto trading% smaller size saved me me some good $$$. But 88%, maybe not this Fed week; but down JAN barometer tends to be down year. Put another way\ Paul tudor Jones gave his clients back a bunch, forced himself/fund to trade smaller.........................