For this game, the big play and long score are the most dangerous with the Giant receivers and Eli Manning....of course, in my sight.
That means that both safeties would have to be strongly involved in a top umbrella. And handle both sides of the field completely. This would take away from the run defense, somewhat.
Myself, I would leave Terrence Newman on the slot receiver and always with an inside positioning to make a play on quick throws. I would give him an early read and a later responsibility, in his man covereage. Double moves would be what he personally is responsible in man coverage and react either way. Give him a simple role...inside pass deflection/interception, or guarding against the deep pass and breaking it up.
I would then break the field up in two halves. That being the box area with linemen and linebackers, and the secondary. That would cover some of the sliding adjustments between the two, from Eli Manning. On running plays, I would call a lot of stunts and blitzes that would bring in four to five players even if it were play action.
Acting independently, somewhat, the linebackers can have multiple roles and move into pass coverages that assists the lanes for the secondary. Carter and Sean Lee should be pretty effective in a deeper role for coverage.
A half-time adjustment would be all important. As the tendencey to pull the plugs and for Manning to sling the leather deep being dependent upon whether they were going for the away game juglar, or to catch up. Otherwise, if they were ahead, and trying to dominate the field and clock, the safeties would be moved up and responsible for play action as before. But push the need for third and longs.
I'm thinking that the Cowboys should force Eli to throw the short pass and bring the heat upon him. May Eli be patient and walk the ball down the field all night, and put the pressure on the Giants to arrive at a viable running game, and not just for the start of the game.
But whether or not the Cowboy secondary has to do their job with or without handcuffs, is dependent upon the Dallas offense. This is one game where the offensive line has to show up at the start of the game, and win a whole game fight for dominance within the NFC East. It's on their shoulders to fight it out this very game. No excuses up front any longer there. In the offensive line's interior, it's either make the grade now, or move along after the season's over.
Even with turnovers, their play is paramount for moving the ball and scoring. That will dictate final outcomes...in my book. The defense is good enough, if there aren't additional burdens continually mounted upon their load.