I have a 2005 16m Wipika Matrix I used back in the day.....
I was over-powered at 16 knots
I was under-powered at 14 knots
..yes it has that one sweet spot at 15 knot
...I then got one of the early Switchblades and was continuously amazed
that a kite could actually have wind range, have depower and be stable...
I still have the Matrix stowed away, I don't think its right to subject
any prospective user to its charms...