RE: Board/sail combo for gusty flat water sailing
I suggested a "not overly big fin", not a "small fin". In other terms, I don't think a huge fin is "the" solution for easy early planing. At least, this is my experience: board, fin and sail must to be in tune between each other; pushing one of the factors too far off balance respect the others results anyhow in worse performances.
Of course, to have something to push against facilitates planing; but on the other hand to have something to push very hard against many many times in "stop/go" conditions will fatigue the sailor earlier and in the end give him troubles in getting to plane.