Whilst it is quite long, I seriously suggest you go back and read the thread in its entirety because after you stopped contributing, there were many healthy discussions and good posts; Medisoft, FXEZ and myself all posted about different ways to tackle the same problems.
If you are looking at using the standard deviations, presumably, typically you might look back in history to see how far they deviate, and determine a particular level/threshold. You would then enter a trade when they breach that threshold? If that is the case, one of the main issues that you need to consider is, if your threshold/entry point is too high, then you will rarely get trade entries. If it is too low, you will get too many which move against you. This is because the SD range differs when the instrument is ranging and trending.
I was looking at a way to trade the SD movements, but trying to take into consideration the trends at the same time. I posted some quite in-depth posts about how I was doing it. From memory, Medisoft also found that too many trades moved against him and the relative drawdown was high. So, good luck if you are going down this road again.