I know it's hard to give bike position advice from an eyeball on the internet, but the recent threads about the A2 vs the Aerohead and others have me thinking if the A2 is optimised for me, or whether I would benefit from a different helmet and/or position change to optimise aerodynamics.

Basically when I ride in aero, the tail of my helmet sticks up a bit off my back.neck, it doesn't sit flush. Is this giving me an aero penalty? Anything I should be doing position wise or even equipment wise (if you see any other red flags) to help get as slippery as possible?