filejw
CON ..1nm for every knot of wind works real well for downwind....
Okay, a little confused here. What wind are you referring to? If it is the upper jet stream winds, that is a bit too much and unrealistic in my humble opinion. I've had upper winds in excess of 150 knots during the spring over the US (lower 48) which is uncommon, but certainly not unheard of.
As GF posted, the stardard is 20 miles downwind which I used for stardard garden variety style thunderstorms. But when a rapid moving cold front is moving across the country driven by jetstreams of over 100 plus knots with tops near FL500, I do give them more than 20 miles, more the better really.
So as you posted, giving them one mile for each knot of speed of the jet stream is great if you have the fuel and can talk ATC into such a large deviation.