After looking at it for a couple of days, I put it in the "too hard to do" pile for now. Here is why:
1. I actually was going to day trade options when I started back in 2013 because I thought the large swings on near expiration options were a good place to double my money every trade. But after observing for a few weeks I gave up because it was too complex a problem for me to calculate the probabilities in real time. Things has not changed, still too difficult for me even by reading charts.
2. Lets run some #: With AAPL, within a 50 day period, there are 8 expiration dates, each date has ~40-50 different call strikes, so using round numbers, there are ~800 different call/put strikes/dates I can trade. If I were to trade spreads to reduce risks, there are 600,000 combinations.
3. To simplify, I can limit myself to just ATM and short duration, 1 day or 8 day expiration, and there are 4 options I can trade. Each has 5 dependent parameters affecting the option prices (using BSM without the fancy corrections for fat tail), three are dominant: time decay, IV and underlying. Time decay I can calculate so not a factor but I still have IV and underlying to worry about.
4. I pick the 8 day expiration and ATM call (the lowest bid/ask slippage): This morning the $143 ATM strike opened ~$1.71 bid and $1.76 ask, changes instantly whenever the underlying moved. the bid/ask slippage is therefore ~ 3% (in trading the underlying, a $0.01 bid/ask for AAPL is 0.007%). The stock moves about 1% a day so the swings in call price could be ~ $0.70 today. The price is correlated to underlying but not entirely, as the IV changes in real time too.
5. I made a few trial run but it was just like a random coin flip with the house taking a 3% cut each time I flipped the coin (to day trade I need to buy ask and sell bid to get quick fill). My conclusion is that I am not smart enough to play this game.
Any comment is appreciated.