exactly, aggregate execution costs are not complex to estimate/compute, but they are not trivial either because various factors flow into the calculation, such as min tick size. Its not all number of contracts/shares on either side...
You're being silly. Have you actually traded ES for a significant amount of time? I've had LMT orders rest of the bid for minutes and then price move away from me, trading SPY you might take the 1 cent loss by hitting it with MKT but that is guaranteed execution. Large min. ticks take money out of my pocket.
