Regardless of the beam, the conditions are 50% of the Beginner/Intermediate/Advanced/Elite equation, nay?
V10, SF, SEI are all similar in that;
-In flat water, they can be paddled 'relatively effectively' by a good beginner
-In small-medium waves it takes a 'solid Intermediate' paddler to put the power down
-In big but not sloppy conditions you're probably pushing 'High intermediate' / 'Low Advanced' status
-In big and or really sloppy conditions, you're probably pushing 'High Advanced' / Elite to fully power the boat at all times
My guess is on the flats it will feel fine, in a big downwinder it may be a handful. I'm about to pick up the SF-S this weekend, and know I won't be out in the 2-3m swell like we had yesterday for quite a while. On the XT it was a handful in big sloppy conditions, but I never went in. I bet I take 2 steps backwards in the SF thru this summer
In my book, 45cm is a Low Intermediate on flat water to High Advanced in sloppy water generally, and could be up to an Elite level boat if the conditions are really big. Likewise, (to me)
V10S is High Beginner to Low Advanced
V12 is Low Advanced to Elite
Edit - you got me thinking, really a boats stability looks like the BMI weight scale. Check out the attached image. This is my entirely non-scientific ranking of beam-to-conditions-to-skill ratio. What do you think?