747-200
An old mate of mine who used to fly the 747-200 once told me that at high altitudes the difference between over speed and stall was barely 6kts - certainly well in coffin corner.
At max likely levels in what I fly the margin is much greater, but if one is flying with such a small margin of only 6kts surely it is necessary to be sure that you are not likely to meet turbulence en route.
Are the margins as small as perhaps 6kts in commercial pax jet aircraft used today? And if so what then does one do to mitigate encountering turbulence when flying, for example the NAT tracks?