Hey other one, I run the 8" centre fin because I want more bite and drive than the original 5.5" offers. But that is me, everyone is different. I don't lay into the paddle to turn like a lot of younger SUPsurfers do so I find the bigger centre fin helps with that.
Can't comment on wind surfing as I have never been into it.
The further back the centre fin the more pivot you get, though you have to get your back foot back further to take advantage of it. These are my thoughts, there are guys on here with much more technical knowledge than me. They might like to comment.
ET.