I'm not part of the team and I've only used smaller fins around 30cm. I prefere the Sr6b as it can take more pressure and it feels more secure in chop. The Slalom Pro I have problems with applying pressure on as it tends to let go, from what I've heard it should be ridden differently with little pressure. You can also do a search on this forum as this has been discussed before, see e.g.
http://star-board.com/forum/showthread.php?t=1499