Tardy said..
colas are you still riding very short boards ..
Yep. Well, actually since I use now wide nosed boards (hybrid noses between a Tomo and a regular nose), I have lengthened my usable rail length, so although still riding a 6'10" in small waves (Gong One), and around 7'4" otherwise (Gong fatal), their rail line give me the stability in turns of longer boards, while keeping the acceleration of short boards.
But this is because I am not attracted to big waves, so I nearly never use my "minigun" 8'4" anymore. I guess this is because after so many decades surfing small waves I am not comfortable with the big conditions (fancy words to say chicken! :-) ), but also that, although you go fast in big waves, I actually feel that your speed relative to the wave is more constrained, limiting your options. Plus the added risks do not seem worth it at my age. So I do not need long boards for taking off in big waves.
Also, I am short, with a narrow stance due to bad hips, so shorter boards are easier to ride shortboard style for me.
On foil profile, yes, this is quite underrated. In the interview on the progression project blog with a FCS guy, he said the pros were liking or not a fin depending mostly on the profile of the leading edge (they liked the sharp front edge of flat-inside fins). Plus the late Alan Byrne boasted to be able to noticeably enhance a board by just spending 10 minutes on its fins with a piece of sandpaper...