John, if you take off with double de-rate, you basically cut a good margin from the Actual temperature Vs Assumed Temperature.
If on top of that you add improved climb speed profile, your initial margin from the highest obstacle in the first, second and third segment is reduced even furthef.
If you Take Off from a relatively flat area, the my risk assessment would say that the directional control stability could be of higher importance.
If you take off from a field surrounded by high obstacles / terrain, my personal risk assessment brings me to believe that the worst danger is the terrain.
On the B737-NG JET, with light weights, high flap settings, -60ºC of temperature and -2000ft, your directional control cannot be impaired by the over trust because you are flying with more than 15 Kts overall margin from the Dragon nest.
But if you, John, want to be super-safe, maybe it is just better not to fly at all! Let the dragon fly for you.
Greetings from a newchum!