I would, @78 kg having different wings and boards, either get
7 m2 Takoon Furia.
9 m2 Takoon Furia.
12 m2 Storm Strutless, but not made anymore, so probably an Ozone Alpha 12 m2.
Would cover foiling from 6 knots up to 15 knots, and then using waveboards when over 15 knots, up to 22-23 knots.
or if I wanted to aim more for surfboards having sweetspot kites -
6 m2 Takoon Furia.
8 m2 Takoon Furia.
10 m2 onestrut Storm V10 Litewind.
Would cover 7 to 17 knots foiling, and again using waveboards when 18 knots and more, up to 25-26 knots.
In either constellation I would miss out on the low end 5-6 knots, and the high end +18 knots (or over 25 knots waveboard)
But would definetely prefer this, instead of having too big gaps, if I could only choose 3 kites.