hi giu
hard to say. I have sailed the SX L 08 and the CA SL70 with 8.4 TR4 and 42cm fin, and IMHO the CA is much more balanced:
- better planning, esp out of the jibe
- and above all more control
indeed, the CA70 compares better to the SX L than to the (69cm) SX M - which I also tried. the latter compares more to the CA SL62.
hence, CAs are slightly narrower (and longer) for a similar sail range than the F2s, and it's my feeling that they offer a more balanced ride, and more performance in both low & high end.
my 2ct
c
ps: I'm 72kg and mostly sail on the north sea (sylt conditions
)