Loosely I can state that it's index-based; meaning that the underlying premise is that vol is -corr to index Px. The index trades are direction and skew on equal weights. The single-names are stat-vol and direction (equal). One index model based upon classic skew mechanics (Derman), but the NDA is based upon one proprietary index model.
Taking a shot with these two: -NDX Jul20 7200/7300/7450 352 fly from 40 risk (40 is reduced to 1-lot equivalent) -SPX Jul20 2750/2775/2825 231 fly from 15 risk (35 cr) I am in the irons in both, included natural fly for illustrative purposes.
Worst movie ever. SPX up 10% on debit. I am walking the dog so haven’t checked the NDX mark, but I assume it’s up marginally. Be back when I get home.