It seems that the margin for an ES options that is close to 100 delta will be very close to being short the future. the future will provide tighter markets with more accurate marks. Also, in the event of a sharp drop in the market, you stop participating at some point. What advantage do you see in selling an options like that to open?
You might get a better execution if you sell the future and the same strike put as a spread. That will likely have a tighter spread. Or, try both and see what does better.
If you look at volume by strike -- whether daily or O.I., you'll notice lumping around major strikes. Would be good to pay attention to that, whether you intend an exit or not.