Hi all, I've figured a model to express my view predicting future volatilities. What is the most cost-effective trading strategy to play my view of volatilities? I am thinking of doing a straddle trade and I am having the following questions: (1) It seems that the spreads of options on S&P500 are huge. What are the options with small/tiny spreads? (2) Is straddle trade the most cost-effective trading strategy for playing the volatilities? Are there other trading strategies that give better performance, such as lower cost, lower risk and potentially higher return. (3) When to enter a trade and exit a trade? During the day, the underlying security keeps changing, and correspondingly my model price of the straddle keeps changing, what should be a good entry point? And what should be the length of the trade? I am thinking of probably 1 day... that's to say, I enter the trade today and exit the trade tomorrow. Since I am doing this using program trading, I need to specify a rule for entering the trade and exiting the trade. What could be a good rule? Is 1-day trade(enter today, exit tomorrow) a good one? (4) Which contract to select? Shall I select the candidate straddle based on the ATM price of the underlying, and/or based on the time-to-maturity, and/or based on the volume of the calls and puts at that current time? How to obtain the volume in the middle of the day? (5) How to take into account the impact of dividends and American style options? If I am using one day trade, will I be able to ignore these two issues completely? I am thinking of trading options on IWM, SPY, and QQQQ, are these American style or European style? It's very complicated to handle a straddle taking into account the dividend issues and American style issues. Hopefully I can ignore these issues? Any thoughts? Please shed some lights on me! Thanks!