Conclusion 1

It’s not speed (or distance) over the ground that counts, IT’S SPEED OR DISTANCE RELATIVE TO THE AIR AT OPENING ALTITUDE.

Popular methods work (most of the time) because winds at 2,500’ are usually fairly light and in the same direction as the uppers.

The worst situation is if the wind at opening altitude is in the opposite direction to the upper winds.

This is OFTEN the case near mountains, large lakes, or coastlines.

The reason these cases lead to results that are contrary to conventional wisdom is that they have been chosen so that the wind at canopy opening altitude is not zero. . THE IMPORTANT FACTOR THAT DETERMINES SEPARATION IS THE SPEED OF THE JUMPSHIP RELATIVE TO THE AIR AT OPENING ALTITUDE. If (and only if) the winds at opening altitude are light, this is approximately equal to the groundspeed. If the winds at opening altitude are in the same direction as the upper winds, then they increase separation between jumpers. If they are in the opposite direction, then separation is reduced. THIS IS NOT AT ALL UNCOMMON, especially near "weathermakers" such as lakes, mountains and oceans.