I wanted to comment on the relative merit of the independent speculator somehow becoming privy to the intimate details of block trades - and if that constitutes an edge.
Having personally taken part in block trades with respect to commercial energy and having witnessed many in the interest rate markets, block trades present a likely illusion as an edge identifier. The executing parties ( let's say GS or MS or BoA or Knight, et al ) are frequently executing orders for institutional clients. So, arguendo just because GS bought 5K ES, does not necessarily mean that the Goldman Sachs proprietary desk is making a bullish bet on the S&P 500 per se. More times than not, they are executing for a client. And to take the logical next step, there is an equally enthusiastic counter party taking the other side of that trade.
As of May, 2016, this is the amount of customer segregated funds Goldman Sachs had on hand:
"13. Total amount in segregation (add lines 7 through 12) $21,431,978,499"
Personally, I would be scared shitless to know who took the other side of my trades. For me, price trumps everything. A block trade, to me at least, simply means two or more parties agreed on a fair price valuation at that space in time. What I am personally much more interested in would be a new price discovery in a new trading range that holds up over time - that tells me that the market has accepted that new valuation and therein the speculator can profit from that information. That's just what I've come to believe over a long period of time, just my 2 cents, YMMV.