Hi there, glad to hear you like it, one of our favoured light wind boards for sure - yes, I think a bigger fin will help with sails over 9sqm, so maybe try a 54/55cm - we found going over 55 seemed to be too big for the board, but you have enough height/weight to leverage the board/fin, so maybe it works to go bigger- the tail is of course not super wide on the LW, so generally not a good idea to go too long on the fin! good luck!