Last year I paddled the V10 Sport extensively in downwind conditions and quickly swapped the Sport rudder for the elliptical rudder because it worked so much better in the waves.
I spoke to Greg Barton about it and he said that Sport rudder is essentially a de-tuned rudder that bites the water less and has less turning moment - giving the paddler the feeling of more stability.
The rudders are interchangeable so you can put the Sport rudder onto the V10 and it should give the feeling of more stability. Once you get used to the V10 however, you'll probably want to go back to the big rudder if and when you go out in downwind conditions.
I found that the V10 Sport with the de-tuned rudder tended to broach easily in the waves because the rudder is shorter and pops out of the water easier.
Have fun!
Rob
Currently Epic V10 Elite, Epic V10 Double.
Previously: Swordfish S, Evo II, Carbonology Zest, Fenn Swordfish, Epic V10, Fenn Elite, Red7 Surf70 Pro, Epic V10 Sport, Genius Blu, Kayak Centre Zeplin, Fenn Mako6, Custom Kayaks ICON, Brian's Kayaks Molokai, Brian's Kayaks Wedge and several others...