I am thinking about purchasing SPX options on the CBOE during Global Trading Hours (GTH). I am wondering, for people with experience doing this, what kind of prices do you see during this time? Are they relatively close to normal trading hours, or do you see highly volatile prices relative to normal trading hours?
The problem is not "the price" - if they were too expensive (cheap) outside of regular trading hours, all you'd have to do is sell (buy) them to make money. But there's no such thing as a simple recipe.
What truly matters, and that it considerably different outside of regular trading hours, is the liquidity on the market. You'll see that the bid/ask spreads are much higher, and the order book gets really thin.
If you trade small, and your edge works even with higher bid/ask spreads, then there should be no problem trading outside of regular trading hours.