Hi could anyone give me any advice on a freestyle fin for an 85 litre quatro 2008 fw. at the moment the fin is 28cm and in a freewave design i guess this makes freestyle moves a fair bit harder than the smaller fins what sort of fin size should i be using on this board for spocks e.t.c? considering it may need a bit more fin to get going than full on freestyle boards?
Any thoughts Appreciated.

18cm should be fine, maybe start with 19cm then you can always cut it down. I would buy as small as possible second hand wave fin then cut it down.

Thanks for the advice, Will the board still plane okay then with a 19cm fin even though it's got quite a wave like rocker??

yeah should be fine as most likely you will cut off most of the rockered part if you start with say a 22 cm one

If you are confident with sailing freestyle boards maybe just go straight to 18cm?