Not scientific answer but here goes
75kg=32knots/36.82mph
So 66kg x 32kn = 2112 divided by 75 = 28.16knots/32.40mph (seem about correct)
For 133cm wide board (that is kind of a wide board for high wind)
For example Toby (90-95kg) uses "128cm" wide board with an 18Dyno in 25 knots in hot/warm wind
So to help your top end and send the kite at edge of window a narrow board helps a lot
So many factors affect lower and upper wind ranges
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