My trend system is fairly effective not only for the S&P, but practically any other daily stock chart. Here's the chart for the US Dollar (ticker UUP). It shows perfectly how the system trips a buy signal.
The USD uptrend (13 went higher than 34) began back in december. However, at the time of the crossover, the price of UUP was too expensive, so the system waits for a pullback to the 34 ema before buying. The ema must hold as support, otherwise, the "buy" never materializes. In this case, the buy occurred Jan 15th...which wouldn't have been a bad day to go into the G-fund.
In an uptrend, the sell occurs when the stock hits the upper bollinger band. In this case, the USD first hit it on Feb 4th. So, the sell was triggered. Using that date to enter the C fund would've been a wise move, as the S&P was 1063 at the close.
So, if the inverse relationship between the USD and stocks continues, one could use the USD chart in this fashion to make IFT decisions.
The interesting thing is that both the S&P and USD are now in uptrends. It will be interesting to see what happens over the next few days/weeks.
System status: 100% G-fund