Apologies if you already know this...but if you want an effective stop loss, make sure that it is set within the bounds of the ATR (Average True Range) for whatever time segment that you are basing your calculations on...i.e. back to the last corresponding (equivalent) support or resistence level. Of course, this also is affeted by your choice of taking a position for twenty minutes / overnight / over the weekend or long term. Usually you want to set your stop comfortably inside the ATR, so that it doesn't get triggerred on the dips (long) or the bumps (shorts). Again, my apologies if you already know this...just trying to help.

Best of luck

LP