Hi hwsteele - Seems like you're making your calls on the momentum of the market during trading. This is not without gutsiness but surely must be tough on the nerves and screen-time, and isn't really swing trading.
You might get a copy of Street Smarts by Raschke and Connors. Its very applicable to the S&P and contains a whole range of set-ups you can identify outside market hours or at the very close, and then place your orders or trades. They always try hard to suggest sensible stops too.