Let's just all agree that below 7-8 knots the wind has a mind of it's own
Too many other factors that have nothing to do with the "speed" comes into play
One of them is spring or fall depending on which hemisphere you kite in
The water is cold and the wind is warm = dense power
An other one is ocean upwelling in the heat of summer when the surface water temp drops tremendously in few days with sideshore wind flow
Etc etc...
So putting up a "number" makes no sense...........and 4 knots is one of them
You either can go riding or you can't with the best gear you have in sub 10
Any of you who have ridden light winds for 22 years knows that
When it comes to ultra light at the "same" wind speed you will have three types
Normal.........8 kn pulls like 8kn
Magical.........8 kn pulls like 12kn
Sucker.......8 kn pulls like 4 kn
That last one can only mean one thing
BEER TIME !!!!