i agree with you because you do not describe your system exactly....
"Use any indicator you like to decide if you will go long or short - doesn't really matter - I use stochastics. Almost anything will work - even something as simple as going in the direction of the previous bar."
but "almost anything will work" is not the case....
annyway If it works for you great keep on doing it.
I see the main problem in limiting profits with a limit order.
FOR ME PERSONALY I found one rule as the moste important one:
let the profits run.
If you manage a trade good you can toss a coin and win over the long run.
The ods that we trader have is to let our profits run. A sports or casino gambler can't do this - if its black it is black it could go darker.....
I see the whole trading thing like gambling but with the big advantage that I can limit my loses and let my profits run.
If I bet on sampres agains agassi I can't add to my position if I see sampres winning.
And if I am on agassi's side I can't say lets go out of the game because agassi is a daddy and not a tennis player

)
That is my trading all about.
Do not take it personally - I have backtested because I was interested in your system and I have poste the results because I think it could be interesting for other traders too.
If you can make money with this system - great !!!!
good trading and god bless america
MW