RE: Max sail size for a board
I'm not involved with "deciding" which sail size span which each board is going to be labeled with. I'm also pretty much a only a wave sailor, so I don't have lots of experience with the boards you mention. But still, my take on the problem is that what kind of sailing the board is intened for makes a lot of difference as does that types of sail that the board is likely to be used with. If we for example compare two boards I have, the Aero 117 (06) and iS101, they sail vastly different (even when the A117 is in freeride mode). The Aero, can be slowly driven onlo a plane and also plane very slowly (but has an extra gear when you go over a certain treshold). It likes to turn, thrives on being pushed down small waves to gain speed etc. The iS101 is in comparasion pretty much all or nothing. In light wind you might need a bit of technique to get it to do anything, but then it just flies off and immediately goes pretty fast. There is just not much in between 5 and 25 knots (of board speed) on the iS (and bring the power on and it will go much faster than that). That the boards get fast so easily means that both the fin and board shape have an easier time handleling that big sail. But again, this asssumes the rider knows a littly bit about what he or she is doing at the very first part of the acceeration phase. On an iS, one can assume the rider has that kind of knowledge (or the will to get it) but the Carve range is intended to ride super easy and not require lot os speciel tricks and hence might be more conservative with sail sizing.