Hey, I am a totes beginner with my 10'7 Red Paddle WindSup (below)
The board came with 2 x small black wave fins. I figured that I needed something bigger in the centre, seeing that I don't have a dagger board, so I bought a 12" Hatchet fin to replicate. I have also bought a 9" Flex Fin. See pics below. (Have had to remove pics as site won't let me post them).
I would be grateful for advice as to which fin combination you think would be best in both (middle and rear).
(An explanation of 'why' would be helpful too).
I am basically learning to tack and gybe and hopefully can get up some speed in lighter winds in the near future.
Thanks again

As big as you can get in the middle and the 9" rear should be good . you want as much lateral resistance as possible when learning so the board doesn't drift downwind
look at pics of an old 1980 learner board side on and you'll see what I mean. However, what you have will still be fine

Cheers Mark