I had success (backtesting) slightly modifying the EA posted above. Instead of the TP and SL above, I optimized looking for a multiplier from -2 to 2 in 0.1 increments to apply to the difference between the high and low. I used tick data from Dukascopy from 2007 to the present and divided it into two sets. With the first set, I optimized for the TP/SL multipliers and the GMT time to trade. I used the second set as a test set, unseen by the optimization.
Best results from test set mid-2008 to 9/30/2010:
GMTtime=7 (edit: in reality it is 8, the code adds 1)
Starting balance: 1000
Net Profit: 393.20
Maximal Drawdown: 129.32 (11.32%)
I'm sure there are flaws in my testing procedures. This is really the first time I've used MT4, although I do have a coding background.