使用抛物线 SAR 进行交易 (trading with parabolic sar)

Hello all:
i want to share a strategy on GBP/USD and i hope that you can send your opinion about this system.
its a very simple strategy that i use to trade on demo account on gbp/usd on m30 time frame.
now lets explaint it:
first of all we need:
1-gbp/usd m30
2-parabolic sar with the priginal setting.
3-time of working is 5:00 untill 17 GMT time zone or close of candle 7 to close of candle 19 meta time.
thats all you need!!
Entry for sell:
1-we will open our sell order 1 pip below the point before the current one....
**-note: you dont see the current DOT because it hit with the candle in signal time,so everytime we work with the dot before the current one for entry.
2-stop loss: we should count the distance between the signal point and current upper point of parabolic sar, then we insert our stop loss one pip above that dot.
3-also we need trailing stop,we will put the stop loss pips on trailling stop too.
4-the target is 2*stoploss.........

buy order is opposit of the sell.
remember that we should calculate the spread and that 2 pip(one pip below for entry and one pip above for stoploss)) in all move........
for example in this picture on 26th april 2007,we should do like this with 4pip spread on gbp in northfinance broker.
sell @ 2.0024 ((one pip below))
stoploss @ 2.0060 ((one pip above)((40pip)
trailing stop=40 pip (like stoploss)
target :1.9940 (2*40)+4spread=84pip
as you see we came out on this order with 80 pip profit. on that day.
it was a good example on my method.
i will send a buy example later...
good luck