There is no such thing as the perfect aero helmet. All major brands make very good helmets these days but it depends on the position and rider style if the helmet is right for you.
Unfortunately wind tunnel testing is not available for me and to do some time trials on a steady loop is very difficult to keep the wattages and the position exactly the same. So I have to do it by looks and feel. I already picked my helmet for Sunday but which helmet you think suits me best and why? I know I have to look forward and not down and I am pretty good at keeping the position but looking down happens sometimes so take that in consideration. A tail can be very aero but can slow you down if it's out of position.