last summer {winter here now with 1 foot snow} i purchased a Fanatic Ultra CAT longboard for light winds
it planes around 10 knots with my 100 kilos

in bigger winds, when the centreboard is raised , it is obviously fin dependent
it has a carbon 30 cm/1 foot fin with a long/wide chord
i find it takes long to turn and was thinking about longer fins
the board is only about 33 to 34 cm one foot forward
have read and heard fin should be no longer than OFO width
is this true ??

www.GSPORT.com seems to have long freeride fins with US box
also read or heard US box is not made for longer fins
is this true ??

also heard or read, with US box if you move fin forward, you get more steering
and back for "control"
is this also true ??

looking for a lot of truth here
that's why i always say windsurfing is like a religion