I'm looking at the Nov 23 ATM ($36) straddle right now, and the bid ask is $3.25/$3.60 which seems illiquid to me.
But, if you could easily bid $3.30 and get filled, that would be ok.
With a spread (bid/ask) this wide, I wouldn't feel comfortable paying the mid point as the trade already has enough risk built into it to add possibly .25 cents getting in, and maybe the same getting out. And that's assuming you can even easily get filled at the mid point.
Win or lose, I feel like you are giving up way too much before the trade even plays itself out.
But, I haven't done this trade so I'm just viewing it from the sidelines.
If you have been profiting then that's great.
It seems to me that the best chances are with using options that have 2-5 days left on them, because they seem to be the most liquid, and have the most gamma,....like when you did the the Nov 16 options.
Also, you would need to be very strict about only holding for 1-2 days at most, maybe even only a 1 day shot, which is why it is SO important to not give up any additional money in the slippage.