slightly below the index number if you’re doing it on someone else’s hand? They will put up half, and I do the other half.
doubling 10 v 10 is slightly negative off the top, returning -.0086 or a loss of .8% of your bet (1/120 or so). So yes, this would be a +EV scavenger double slightly below the index, in fact it probably only takes the count to be slightly positive before you can make money with this play.