If waves/side-sideonshore, often waveboard from around 17 knots and up, with a 9 and 7 and 5m2.
Occassionally with an 11m2 if sideshore and good waves in 14-16 knots only.
For light wind sub 13 knots as asked for:
12-13knots (actually up to 15) - 9m2 Takoon Furia (depower/wave kite) and Zeeko Makaira Hydrofoil Racewing or Freeridewing.
Only for lighter wind is bigger than 10m2 used
9-11 knots - 11m2 Furia and Hydrofoil.
8-9 knots - 13m2 North Dyno, 28m lines, and Hydrofoil.
7-8 knots and less - Elf 15m2 Joker and Hydrofoil.