I recently purchased a 2011 Cabrinha Race 183x59 and am really enjoying it, especially in light wind. It has the stock fins which I believe are about 20 cm long.
What do longer fins get you? Better upwind performance is obvious, but do they increase or decrease your low end? Is it harder to tack and jibe with longer fins?
My biggest problem getting used to the race board is trying to keep the board flat. With the footstraps all the way out on the rail I'm always edging too much (digging the heelside in).
I'm guessing the way this footstrap position is supposed to work is the windward heeling moment of the rider standing out on the rail is counteracted by the leeward heeling moment of the lateral force from the kite against the fins. Longer fins would mean more resistance from the fins and a longer moment arm, so wouldn't it be easier to keep the board flat with larger fins?