11 too small as a primary kite, you'll need 13/14, depending on board, style etc. Probably a 9 for windy days.
Ideally, no more than 3m between kite sizes and you'll get on the water more with 3 kites. An option is to get a 15 or 17 for lighter days, then you can go with a smaller "main" kite.
9/12/17m kites 140x43 small board for strong wind145x45 every day board 165x48 light wind board. then you can kite most days instead of sitting on the beach with everyone else waiting for perfect conditions for your gear.
