IMO the Akuji UL needs at least 3 mph to be an easy fly for those of us who are not yet able to generate a PWM (*) -- will fly in less, but needs a deft touch that I certainly don't possess yet, but it's OK up to about 8 mph (gets a bit noisy, but is still perfectly flyable).
Again, for those of us without PWM, the SUL needs at least a "just about feelable" wind. I was flying it on Saturday when the wind was varying between "just about feelable" and 6-ish mph.
Incidentally, Chris Goff (who does seem to carry a PWM) put my SUL through its paces in just about zero wind at Dunstable on Friday night. Absolutely beautiful to watch this kite in the hands of someone who can
really fly! Yet again, I get the message that the limitation is the flyer, not the kite: try harder, Tonkin!
(Mind you, I'm sure that young Mr Goff could make an old Tesco bag on the end of a length of sisal parcel twine look good!)
* Personal Windy Microclimate