Individual equities or ETFs. The aggregate bid/offer on index options can exceed the debit risk at FairVal. Google is a fantastic stock for trading complex positions as the vol is large yet trades discrete. Where else can you find a $400 stock that trades a nickel bid/offer? Also, the vol smile MOVES on Google, and often the smile moves > the -20d to +20d strip vols. Truly the tail that wag the dog. Yes, a neutral delta "long" fly will always carry a short gamma/vega position. ITM verticals, among others.